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Where Oh Where Should My Purlins Go?

Where, Oh Where, Should My Purlins Go?

There are almost as many methods for assembly of a post frame building, as there are post frame buildings! I kid you not.

Amongst differences are how to space trusses – two, four, eight, 12 foot or numerous other possible centers. Along with different truss spacings are how to install roof purlins across or between trusses to support steel roofing.

Reader KELLY writes:

“So, I would like some info on purlins. One builder has them laying flat on top of truss, one on edge on top of truss, and one on edge with hangers between trusses? I have my thoughts but wonder what is technically better.

I like the hanger between trusses, for roof load, but I wonder if you give up some of the diaphragm strength that is accomplished by purlins laying flat on the truss.

To me, with a purlin that lays across multiple trusses, you get the benefit of added strength because you are tying multiple trusses together and the lateral stress is on the edge of the purlins. When they are in hangers, the load stress in on the purlins edge, but the lateral stress allows the trusses to move independently.

Trusses most likely on 8’s. Purlins 24 spacing.”

Mike the Pole Barn Guru writes:

Purlins placed flat will not span eight feet, so eliminates this option. If you are planning upon going with edgewise purlins across a single truss, you are going to run into an uplift problem. Usually builders want to drive a 60d nail through purlins, into truss tops, however this connection doesn’t calculate out as being able to keep purlins from ripping off the building during severe weather. Most builders are not willing to spend time to install an engineered steel tie-down for purlins in this scenario. Over top also means purlins get staggered when they overlap. This precludes abilities to predrill roof steel. Predrilling gives nice straight screw lines and also eliminates possibilities of missing a purlin with a screw.

This leaves “in hangers” between trusses as your only viable (and practical) design solution.

Diaphragm stiffness of your roof will come from your building’s roof steel (and method of attaching steel to purlins), not how purlins are connected to trusses. Purlins tying multiple trusses together are not going to make your end resultant any stronger or stiffer.

Ultimately your RDP (Registered Design Professional – architect or engineer) who places his or her seal upon your building plans will be making a determination as to adequacy of any of these connections. If you are talking with a builder whose brilliant idea will be not building from engineered plans …run away from them as quickly as possible. This would be a risk not worth taking. If an engineer didn’t design your building…..then who did?

This entry was posted in Pole Barn Planning, Pole Barn Structure, Trusses, Pole Barn Questions, Pole Barn Design and tagged trusses, pole building plans, building plans, registered design professional, purlins, 60d nails, pole building diaphragm on January 22, 2026 by Rick Ochs.

Sealing Gaps, a Moisture Problem, and Girt/Columns/Wiring advice

This Wednesday the Pole Barn Guru answers reader questions about how to best seal gaps at wall tops and a roll-up coil door, creating a moisture problem, and advice for girts, columns, and wiring.

DEAR POLE BARN GURU: What can I do to seal these gaps? We live in the garage and it’s getting cold out. TIFFANY

DEAR TIFFANY: There should be inside closure strips on top of eave strut under your roof steel. On endwalls, emseal expandable closures can be placed between rake trims and endwall steel. There should be a flat (wide face to sky) jamb across top of roll up door opening. These would help to seal around door opening https://www.snirtstopper.com/

DEAR POLE BARN GURU: I have one more question for you I have a cabin that has 2×6 stud walls 12′ high that I put 2″ foam under slab and 2″ on the side walls so from under slab to top of walls on the exterior is completely covered in foam with 2″s of closed cell spray foam sprayed to the interior of the 2″ pink. Then 5″s of closed cell sprayed on the roof for a hot roof. My problem is I’m heating this building with electric boiler and my bills have been quite high. In the house side I have vaulted ceilings so not much I can do there but my garage ceiling is 12′ with no insulation at that level because of the hot roof in your opinion if I blew in insulation at the 12′ ceiling height what would you do between the blown in and hot roof I’m worried about creating a moisture problem and mold and thinking I should vent that area above the garage too the outside what’s your thoughts thanks. CHRIS in HIXTON

DEAR CHRIS: Very valid concern. You would need to vent at eave and ridge. Make sure to leave at least an inch of unobstructed airflow between top of blown in insulation and underside of roof deck, from eaves to ridge.

DEAR POLE BARN GURU: 1. Are properly blocked and attached bookshelf girts between 6×6 posts 4 ft on center without any exterior girts an acceptable approach? Same question for the purlins for the trusses. 2. Instead of adding the one and a half inch on the girts board, is it an acceptable practice to drill through the 6×6 posts for wiring? ERIC

DEAR ERIC: 4 foot on center makes for an awful lot of holes to dig and posts to set, not to mention becoming very limiting on width of openings like windows. We would recommend (of course with engineer’s approval) glulaminated columns every 12′ or even 16′). Outside of this, it is an acceptable approach, provided you can attach your splash plank to adequately transfer shear loads. We always recommend insetting roof purlins between trusses using engineered hangers.

Think of a hole being drilled through as being an “open knot”. Lumber grading rules refer to these as being “Unsound or Loose Knots and Holes” due to any cause.

For #2 graded lumber holes may be no less than every two feet and up to 5/8” diameter in a 2” nominal face; 7/8” in a 3” nominal face; 1-1/4” for 4”; 1-1/2” for 6”; 2” for 8” and 2-12” for 10”.

For higher grades holes may be no less than every three feet and up to ½” diameter in a 2” nominal face; ¾” in a 3” nominal face; 1” for 4”; 1-1/4” for 6” and 1-1/2” for 8” and wider.

Any holes drilled through pressure preservative treated lumber or columns, especially near grade, should be treated with a Copper Naphthenate solution. Copper Naphthenate is available as a brush-on or spray-on.

This entry was posted in Pole Barn Heating, Barndominium, Ventilation, floorplans, Lumber, Insulation, Pole Barn Questions, Building Interior, Pole Barn Design, Columns, Building Overhangs, Constructing a Pole Building, Pole Barn Planning, Pole Barn Homes and tagged insulation, condensation, Ventilation, closures, girts, seals, purlins, sealing gaps, EmSeal expandable closures, post frame wirng, vented closures, column spacing on November 12, 2025 by Rick Ochs.

Thinking Stick Frame Rather Than Post Frame

Thinking Stick Frame Rather Than Post Frame

Reader BRAD writes:“Real question…I’ve been doing lots of reading and love this site. I am building a 40x60x14 this spring. I originally thought I was going to go pole barn and now I am thinking stick frame. Reason….1. I am going to have insulated concrete foundation with in floor heating piping installed right away. (mono slab). 2. I am planning on fully finishing the inside insulation electrical, etc. in the future. What I’ve seen with post frame is that they are cheaper to build initially but if you are planning on finishing the inside there is substantial lumber and framing that needs to be done for interior walls and interior ceiling. It appears “at the end of the day” a finished pole barn is not much cheaper than a stick frame. I also question if it would be a lot more time trying to frame an interior post frame with 16” o/c studs and finishing a ceiling with 4’ or longer truss spacing vs 2’ with conventional stick frame. I am doing all metal exterior with 2’ o/c stud purlins on side walls vs osb sheathing. I know you can spray closed cell spray foam but again that is more than triple the price vs bats and vapor barrier that you can only do with 24”or16” o/c framing.

Am I way off base on this theory or is there any truth to my thinking?”

Mike the Pole Barn Guru responds:
I just don’t see reason number one as a reason at all. A plethora of post frame buildings (my own included) utilize radiant in-floor heat. In order to stick frame, you are going to have to thicken your slab edges, or pour a continuous footing and stem wall, in order to provide adequate support for your now load bearing walls. This is going to result in added expenses for forming, regardless of your choice (before even considering extra concrete required). While anchor bolts for stud walls are relatively inexpensive, they do require some effort to be properly placed in order to avoid hitting studs and plates need to be drilled to account for them.

In order to stick frame without added engineering, your wall heights are going to be limited by Building Codes. To attach steel siding, you will need to add horizontal framing outside of your studs (scarily, I did see a builder post photos of vertical steel siding, screwed to vertical studs), resulting in two sets of framing, extra pieces to handle, cut and install. By using commercial style bookshelf wall girts in post frame, no extra framing is required in order to attach exterior steel siding and wall finish of your choice. As post frame buildings transfer gravity loads from roof-to-ground via columns, eliminating (in most instances) any need for structural headers.

Using prefabricated metal connector plated wood trusses, in pairs, directly aligned with columns (most often placed every 12 feet), does require ceiling joists to be placed between truss pairs. This can all be done on the ground, then cranked into place using winch boxes, with no need for other heavy lifting equipment.

When all is said and done, fully engineered post frame construction will always be more cost effective than stick frame, more structurally sound and afford a greater ability to super insulate, regardless of one’s choice of insulation systems.

This entry was posted in Pole Barn Structure, Trusses, Concrete, Pole Barn Questions, Columns, Pole Building How To Guides, Pole Barn Heating, Pole Barn Planning and tagged pole barn truss spacing, closed cell spray foam, truss spacing, stick frame, insulation, lumber framing, pole barn, purlins, osb sheathing on October 23, 2025 by Rick Ochs.

What Kind of Trusses Are Pictured?

This question was posed by Hansen Pole Buildings’ Designer Doug. Photo isn’t of a Hansen Pole Building, probably raising questions in Doug’s mind as it looks rather foreign.

Only actual trusses in photo are in raised center portion of this monitor style building. Interior trusses were probably sold to building owner as being “double trusses”. In actuality this system has only a single truss placed upon each side of columns. These trusses, even though only inches apart, do not load share. They are only as strong as weakest individual truss. Between trusses, sticking up beyond top of top chords are paddle blocks (read about paddle blocks here: https://www.hansenpolebuildings.com/2012/05/paddle-blocks/) to attach roof purlins.

Monitor wings (or side sheds/lean-tos) have rafters placed each side of columns with paddle blocks as well. Second floor (aka loft) extends out into wing areas, although quickly loses functionality as headroom decreases close to eaves.

More headroom could have been garnered throughout entire second floor had trusses and rafters been positioned to allow roof purlins to joist hang into their sides. When placed as “top running” purlins, interior clear height decreases by purlin thickness. Positioning of roof trusses as lowered, below purlins causes builder to have to frame outriggers (or tails) above truss in order to support sidewall overhangs. Each paddle block makes for a purlin stagger and eliminates one’s ability to predrill roof steel panels. This adds to possibilities of roof leaks being created by each stagger point.

Other concerns exist in this photo. Where roof purlins overhang single end truss, attachment has been made with yet another set of paddle blocks. With an assumption overhangs will be enclosed, this allows for outside air to enter in spaces created between purlins. This decreases efficiency of dead attic space airflow from eaves to ridge.

Solid blocking should be placed between end overhanging purlins to provide continuity of a load path from roof diaphragm to ground. As being built, load path has been divided.

Perimeter beams in this photo show to be inset between the columns. My curiosity wonders how they adequately attach? Your guess is as good as mine.

This entry was posted in Pole Barn Structure, Trusses, Pole Barn Questions, Pole Barn Design, Building Overhangs and tagged double trusses, purlins, single trusses, lean-to, paddle blocks, outriggers on May 29, 2025 by Rick Ochs.

Twelve Foot Addition, Wall Insulation, and Purlin Settings

This Wednesday The Pole Barn Guru answers reader questions about extending an existing 60′ long pole building by twelve feet, the best way to insulate outside walls to prevent sweating, and the reasoning behind setting purlins flush with the top of the truss top chords.

DEAR POLE BARN GURU: I have an existing 40 x 60 pole building, built in the late 80’s. It has double trusses spaced 12 ft apart. I would like to extend it from 60 to 72 ft. We originally were thinking we would extend using stick frame construction but now I am wondering if this will affect the integrity of the existing building. I would like to leave the end of the pole building in place and add a door into the new space at each end. Your advice on the best way to go about this? The extension is planned for a bathroom and laundry space and would have a concrete floor. Thanks for your help. WENDY in VANCOUVER

DEAR WENDY: Adding as a post frame (pole) building will be your most economical and easiest route to go, especially as your Building Department will require engineer sealed drawings and verifying calculations. In order to determine how best to achieve your end goals, we would need detailed photos of inside and outside of your existing building, measurements at eave sides and dead center from bottom of pressure preservative treated splash plank to underside of roof steel, spacing of existing endwall columns, etc. We make deliveries into Western Washington and Northwest Oregon frequently, so freight costs will be quite reasonable. Please forward your information to Caleb@HansenPoleBuildings.com along with site address and best contact phone number.

DEAR POLE BARN GURU: I built a pole barn last year and am having the floor poured this week. Once completed, I will begin building an apartment inside the barn area. What is the best way to insulate the outside walls for great R value and prevent sweating? DAVID in PORTSMOUTH

DEAR DAVID: If you placed a Weather Resistant Barrier (think Tyvek or similar) between your framing and siding, then fill your insulation cavity with Rockwool and have a well sealed vapor barrier before interior finish. If no WRB, then have two or more inches of closed cell spray foam applied to inside face of your siding, then fill balance of cavity with rockwool and no interior vapor barrier. Depending upon what you do with your under slab and roof for vapor barriers and insulation, you may need to mechanically dehumidify in order to prevent condensation (sweating), as your walls alone are merely a small piece of a big puzzle.

DEAR POLE BARN GURU: I understand your roof design is with purlins flush with the top of the truss. Why do you use this design? Sorry if this info is on your website, I didn’t see it. Regards, STANLEY in DOSWELL

DEAR STANLEY: Here is an article on this subject: https://www.hansenpolebuildings.com/2019/02/where-oh-where-should-my-purlins-go/

Having roof purlins flush with top of trusses has many advantages:

It does not take up extra height (purlins over top of trusses either reduces interior clear height or increases eave height).

Purlins are then in perfectly straight lines, allowing for pre-drilling of roof panels (this eliminates misses). Others may try to align purlins over top of trusses using butt end splices. This makes for a very poor connection attempting to get adequate fasteners into 3/4″ (1/2 width) of truss top chords. When purlin joints are lapped, it causes a stagger of the purlins, resulting in inability to pre-drill and a significant chances of screw misses.

Purlins can be connected to trusses using engineered and Code conforming parts (in our case, quick to install Simpson Strongtie PFDB26B). Codes (as well as sound engineering practice) require purlins on edge to be solid blocked or otherwise prevented from rotation at ends. A nailed only connection would not meet this requirement).

This entry was posted in Columns, Constructing a Pole Building, Sheds, Pole Barn Planning, Pole Barn Structure, Barndominium, Footings, Rebuilding Structures, Pole Barn Questions, Budget, Pole Barn Design and tagged addition, post frame addition, insulation, condensation, PFDS26B hangers, Ventilation, extension of building, wall sweating, purlins on September 11, 2024 by Rick Ochs.

Can This Building Be Saved?

Can This Building Be Saved?

Reader BRAYTON in NORTHEAST WASHINGTON writes: “I’ve been previewing your website and am glad I found it!

Question:

I have been contacted recently by a potential client who had a 40′ x 60′ pole building constructed. The original contractor walked off the job. This client wants me to fix the building.

Here’s the situation:

The trusses are sheeted with OSB on one side of the gable trusses. The trusses are leaning toward one gable end. They appear to be warped and seem to have been installed this way. I figure this because the gable ends are not leaning as much as the trusses. The roof purlins are mounted to purlin blocks on top of the trusses and have joints meeting at each set of double trusses (the trusses are mounted on either side of the post).

The trusses were not braced laterally across the bottom chord, nor cross-braced at either gable end. There are missing wall girts and there doesn’t appear to be any bolts and/or hardware attached. The structure sat through a north eastern Washington winter like this. Half of the OSB roof sheathing was installed this spring, when the contractor walked.

The posts are not in line. The posts at the gable ends are inset from the wall posts. The owner states the posts were backfilled with sand. The existing soil has a lot of clay/dirt.

So, is this building salvageable? I was considering temporarily bracing the trusses, removing the roof sheathing, loosening the purlins at one end, and then truss by truss attempt to plumb them – bracing them as I go.

If you have any suggestions, I’d appreciate it.

Thank you.”

Thank you for your kind words. We would be interesting in talking more with you about future builds (please reach out to Rachel@HansenPoleBuildings.com 1.866.200.9657 Friday). Yes, it can be fixed. It will not be cheap – personally I would look at quoting either an hourly or daily rate, plus any equipment rental, as you will have no idea what you are getting into, until you are there. I’d think if you get it stripped down to framing, you could properly align columns (make sure to check if it is even square). Get one endwall straight and plumb, then adjust purlins bay-by-bay, as needed, to straighten each set of trusses.

This entry was posted in Rebuilding Structures, Budget, Pole Barn Questions, Professional Engineer, Pole Barn Design, Columns, Constructing a Pole Building, Barndominium, Pole Barn Structure, Trusses and tagged truss bracing, purlins, columns, trusses, Saving a building, post frame building on July 9, 2024 by Rick Ochs.

Insulation, Lean-To’s and a DIY

A Bonus Ask the Guru for this Thursday’s blog for Insulation, Lean-To’s and a DIY

DEAR POLE BARN GURU: I have a 30×40 pole barn with 6″ purloins mounted between the posts. I’m planning to add minimal insulation using closed cell panels. I’ve seen recommendations to cut the panels to fit between the purloins (would be up against metal) ang using great stuff to seal gaps/seams. I’ve also seen recommendations to attach panels to inside of purloins and seal with tape, which would leave roughly 5.5 inch air gap. However, the air gap would have little real ventilation due to the purloins. It would just be lots of “pockets”. I plan on putting 1/2 inch plywood over the insulation. Note…this is a coastal area with direct sea breeze and I’m only insulating about half of the barn, if that matters. Interior walls with fiberglass batting will separate the heated/unheated areas. RAY in SOUTH BEACH

DEAR RAY: Other than if you intend to use closed cell spray foam insulation applied directly to underside of your roof steel, there is no other ‘right’ way to insulate between your roof purlins. Here is a story from another person, in a similar situation: https://www.hansenpolebuildings.com/2023/10/properly-insulating-between-roof-purlins/

DEAR POLE BARN GURU: I’m wanting to add a 20′ lean to my 40x60x14 barn. Lean I would like is 20x60x12 but not sure if this work? What size do lumber for rafters for that span and how close together? Put 29ga metal on roof enclosure of 2 ends

Thank you. ALAN in MERIDEN

DEAR ALAN: Adding a lean to may look quite simple, but can be fraught with unknown challenges.

Your existing building should be checked by an engineer to insure columns on side you are attaching to are adequate for newly imparted loads. Rarely will footings along this side of your existing building be adequate in diameter to now have to support twice as much load as originally intended. Snow drift zone (along each side of ridge of existing building), will become significantly wider on side of ridge opposite your lean to addition.

It may prove most prudent, to place another set of columns every 12 feet along your existing building sidewall to support your lean to. This would also eliminate having to cut into your existing wall for attachment.

If your intention is to clearspan 20 feet rafters will probably have to be either LVLs (Laminated Veneer Lumber – read more here: https://www.hansenpolebuildings.com/2015/02/lvls/ ) or we have ultra high strength lumber available to fabricate wood roof trusses with your very low slope and not take up any more headroom than absolutely needed.

Another consideration is your proposed 1.2/12 roof slope will void paint warranties on your new addition roof steel.

DEAR POLE BARN GURU: Hi, I’m very interested in getting one of these, but do you install them? Or do I need to find someone who knows how to? The answer will determine whether or not I buy. ROBEY in CERRILLOS

DEAR ROBEY: Hansen Pole Buildings are designed to be erected by any average physically capable person who can and will read directions. We have had clients from septuagenarians to father’s bonding with their teenage daughters successfully erect their own beautiful buildings, often saving tens of thousands of dollars while doing so.

Thousands of DIYers, in all 50 states, have built their own Hansen Pole Buildings. You can see photos of their work on our website.

Your engineer sealed building plans are specific to your building, on your site and include location and connections for every member. Details on plans are keyed to specific sections of our step-by-step Construction Manual guiding you through every phase of assembly. Even your lumber package comes with board ends of specific members color coded to match their location on your building. You don’t even have to drive nails, as we provide structural screws for assembly!

Get stuck, can’t find an answer or just want to confirm something? Our Technical Support team (who have actually built buildings) provides unlimited free assistance.

While some of our clients do hire building erectors, it is certainly not a necessity to do so (and no, we are not building contractors in any state).

This entry was posted in Barndominium, Trusses, Ventilation, floorplans, Building Interior, Budget, Insulation, Professional Engineer, Pole Barn Questions, Columns, Pole Barn Design, Sheds, Roofing Materials, Pole Barn Planning and tagged building erector, purlins, lean-to addition, lean-to, DIY, insulation on May 30, 2024 by Rick Ochs.

Greyed Lumber, Insulation, and Flat Purlins over Trusses

This week the Pole Barn Guru answers reader questions about cleaning up rough cut lumber that has greyed from exposure to the elements, advice on house wrap and insulation, and the ability of flat purlins over trusses to carry a load in Kentucky.

DEAR POLE BARN GURU: My barn project has been a long drawn out process. The project stalled for 6 months but has picked back up again. I’m using rough cut lumber. Unfortunately, the wood has a grey color to it (probably from dirt, mold or algae on the surface).

What’s the best way to clean it to make it look fresh/revived again? Any products that you recommend?

Thank you again for all your help and advice. JAMES in MILTON

DEAR JAMES: Clean with sodium percarbonate or hydrogen peroxide, then apply oxalic or citralic adid (second step restores wood to its natural pH and neutralizes sodium percarbonate cleaner).

DEAR POLE BARN GURU: I added a lean-to to my 60×90 pole barn. The builder put house wrap around exterior walls. When the tin guys put up the metal they put bubble wrap over the house wrap then the metal. I spray foamed with closed cell inside 2 inches. The interior will be knotty pine so do I need to put another barrier before the wood? Also on the roof they put the bubble wrap under the steel I will have blow in on top of the knotty pine. I plan on putting plastic sheathing before the knotty pine. Is this the correct way of doing or should we change something? SCOTT in KOUTS

DEAR SCOTT: It was bad enough when your tin guys put bubble wrap over your housewrap. Compounding your having spent your hard earned money on both, is closed cell spray foam should have been applied directly to inside of steel siding. Water under a bridge at this point. You should fill balance of wall cavity with unfaced rock wool and no interior vapor barrier. Wall will now dry to inside (meaning you may have to mechanically dehumidify). You did not say if your added lean to has an attic space or not. If your intent is to insulate with plane of roof (purlins) here is some guidance: https://www.hansenpolebuildings.com/2023/10/properly-insulating-between-roof-purlins/

If you are insulating above a lower ceiling height (as you say blow in – I will guess this is your case), in your Climate Zone 5A a vapor retarder should be on warm in winter side of insulation (not a vapor barrier, like plastic sheeting). A vapor retarder could be as simple as kraft facing from batt insulation, or latex ceiling paint. Make sure to adequately vent any non-conditioned attic space.

DEAR POLE BARN GURU: I love reading your posts. I’ve learned much about your ideas and it’s changing the way I think. Thank you. Iowa and SD have different wind and snow loads than central KY. I routinely see farmers building barns with 2×4 purlins laid flat on trusses spaced every 8 feet. Your designs call for 12 spacing, which I love, and 2×6 purlins on edge in joist hangers. Would 2×4 purlins in joist hangers work in central KY?

CHRISTOPHER in RICHMOND

DEAR CHRISTOPHER: Thank you for your kind words.

We have provided fully engineered post frame buildings in places with no snow, to places where snow load is over 400 pounds per square foot – so we have pretty much seen it all!

Those farmers laying 2×4 purlins flat (wide face to sky) spanning eight feet are risking not only their buildings, but their lives. I am amazed they can even apply roof steel to them without failures.

For 12′ spans, without snow, purlins on edge, 2×4 2400 msr roof purlins 24 inches on center would carry loads, however would overly deflect. You could probably use 2×4 #2 Southern Pine at 12 inches on center, however 2×6 #2 at twice spacing would be more economical both in materials and labor.

Read more about msr lumber here: https://www.hansenpolebuildings.com/2012/12/machine-graded-lumber/

This entry was posted in Pole Barn Planning, Ventilation, Uncategorized, Building Interior, Lumber, Insulation, Columns, Pole Barn Questions, Pole Barn Design, Barndominium, Constructing a Pole Building, purlins and tagged grey lumber, insulation, gray lumber, spray foam, rough cut lumber, moldy lumber, purlins, Kentucky building, flat purlins, house wrap on February 21, 2024 by admin.

Why Are You Stuck on Bookshelf Girts?

Why in World are you Stuck on Bookshelf Girts?

Reader JAMES writes:

“Why in world are you stuck on bookshelf girts. For instance with ‘normal’ pole barns one could SPF the walls and roof and have almost no heat loss through the lumber. One could argue your “bookshelf girts” and purlins between trusses makes the building VERY close to a “normal home”. Do you offer a traditional style built pole barn as there MUST be savings to be had.”

Mike the Pole Barn Guru writes:
There are as many ways to structurally design post-frame buildings as there are providers and builders. Our way of building happens to be very similar to what would be considered as traditional style in Western states such as Washington, Idaho, Oregon, California, etc.

We do happen to offer buildings with columns every eight feet, trusses every four feet – however very few clients ever pick this as an option.

We are always looking at ways to make our post-frame buildings more efficient and DIY friendly, without sacrificing performance.

Worst part of post-frame construction (and least easily to detect challenges in advance) is having to dig holes. By widely spacing columns (usually most cost effective is every 12 feet), number of holes having to be dug is reduced by roughly 1/3rd from eight foot spacings.

Let’s examine R-value, calculated using Type 1, conventional method.

For sake of discussion, we will use an 18 eave height (tall enough for two stories in most instances). I’ve chosen a flash and batt method, for sake of cost effectiveness of insulation.

R-value through cavity

Air film – inside 0.67

½” gypsum wallboard – 0.56

2” closed cell spray foam – 14

5-1/2” Rockwool – 23

Exterior cladding – 0.5

Total R = 38.73

R-value through girts

Air film – inside 0.67

½” gypsum wallboard – 0.56

2×8 girt – 9.06

Exterior cladding – 0.5

Total R = 10.79

On an 18’ wall, in one 12′ bay there will be 8 girts with an area of 1.5” x 144″ x 8 = 1728 square inches or 12 sft (Square Feet)

Total area of a bay = 18’ x 12’ = 216 sft

Hence girts makeup 12 / 216 = 0.056 (5.6%) of wall

10.79 x 0.056 + 38.73 x 0.944 = 37.16

37.16 / 38.73 = 0.959 (95.9% of a wall without girts)

How about pieces in say a 60’ long wall?

Your “traditional”

Splash planks: 1/12’ 3/16’

Girts: Exterior 2×6 8/12’ 24/16’ Interior 2×4 8/12’ 24/16’
NOTE: Exterior girts may fail in deflection, especially at wall corners where forces are greater

Columns (excluding corners): 7/22’

Truss carriers (will vary depending upon roof load): 2×12 2/12’ 6/16’

Me:

Splash planks: 5/12’

Bookshelf girts: 2×8 40/12’

Girt blocking: 2×4 10/16’

Columns(excluding corners): 4/22’

Your version has me handling 74 pieces of lumber, with 1582 bd.ft. (board feet) of lumber vs. 59 pieces with 984 bd.ft. of lumber

Your wall sets outside of external wall girts at Building Line and creates an 8-1/2” thick framed wall. On a 40’ wide building, net framed interior clear width is 38’7”.

My wall has outside of columns at Building Line, so only 5-3/4” is lost on each side. Net framed interior clear width is 39’0-1/2”

In summary, my being stuck on bookshelf wall girts loses only 3.2% to thermal bridging, reduces holes to be dug (per sidewall) by 43%, reduces pieces to be handled 20% and board footage of lumber used by 38%, while delivering a greater net usable interior space.

This entry was posted in Insulation, Pole Barn Questions, Pole Barn Planning, Trusses, Concrete, Pole Barn holes and tagged rockwool insulation, flash and batt method, gypsum wallboard, trusses, exterior cladding, bookshelf girts, eave height, purlins, closed cell spray foam on November 21, 2023 by admin.

How To Vent An Attic Below A Lean-To Porch

How to Vent Attic Below a Lean-To Porch

Long time reader JON in SPRINGDALE writes:

“Hi Mike, long time reader. Thanks for the info you provide. These questions come from your

home town area. I was talking to my local building department and attic ventilation came up. He

said that using a ridge vent and vented soffits isn’t enough, because the purlins restrict the

natural air flow between the two. So he suggested powered gable vents. I believe code calls for 1″ minimum clearance between insulation and sheeting what would you recommend as this affects the size of the heel on the trusses. Still on attic ventilation, so I want a porch covered by a lean to with a continuous roof line peak to eave. My question is if the underside of the lean-to is open, how do I vent the attic with no overhang to put vented soffit on? Thank you.”

Mike the Pole Barn Guru says:

I have been unable to find any published research to back up your inspector’s theory, nor would anything in written Building Codes support use of powered vents as a method of either intake or exhaust to meet Code requirements. Code does require a minimum one-inch space between top of blown or batt insulation and bottom of roof deck.

To ventilate eaves on side of building with continuous roof and covered porch, you could oversize eave strut (purlin at top of wall between enclosed portion and porch) to say 2×10. Cut notches into top edge of purlin an inch deep, by whatever length would be necessary collectively to meet proper ratio of eave air intake to exhaust. Notches would need to be covered with Code compliant screen to restrict entry of small, flying critters and wall steel stopped below bottom edge of notch.

In summary, ventilation requirements in IRC’s 2018 edition are as follows:

Provision of one square foot of NFVA for each 150 square feet of attic floor. One important note – attic floor area is just as it reads – area – not volume. This is a minimum requirement and does not stipulate required ventilation openings provide intake (low), exhaust (high), or both.

Provision of one square foot of NFVA for each 300 square feet of attic floor if both following conditions are applicable:

A Class 1 (≤ 0.1 Perm) or 2 (> 0.1 to ≤ 1.0 Perm) vapor retarder is installed on warm-in-winter side of ceiling when the structure is located in climate zone 6, 7, or 8.

At least 40%, but not more than 50% of NFVA is provided by vents located not more than 3 feet below roof’s highest point.

Provision for a minimum one-inch air space between roof sheathing and insulation in attic at vent location.

There are a few items I would suggest, after looking at your provided portion of plans.

Do away with all of expensive OSB sheathing. Order roof steel with an Integral Condensation Control factory applied.

Increase ceiling height to 10′ 1-1/8″ from top of slab to bottom of trusses. This will allow you to use 10-foot sheets of gypsum wallboard (sheetrock) run vertically without cutting.

Use bookshelf wall girts to create an insulation cavity and for ease of interior finish.

Have your engineer check purlin spacing on each side of ridge to account for drift loads. Purlins at high side of dropped right side porch also need to be checked for slide-off and drift loads.

Code requires a minimum 6mil vapor barrier under concrete slabs on grade in conditioned areas.

This entry was posted in Pole Barn Planning, Trusses, Porches, Pole Barn Questions, Pole Building How To Guides and tagged purlins, osb sheathing, attic vents, lean-to, integral condensation control, NFVA, IRC 2018, attic floor on October 10, 2023 by admin.

Thinking Stick Frame Rather Than Post Frame

Am I way off base on this theory or is there any truth to my thinking?”

This entry was posted in Pole Barn Questions, Columns, Pole Building How To Guides, Pole Barn Heating, Pole Barn Planning, Pole Barn Structure, Trusses, Concrete and tagged purlins, osb sheathing, pole barn truss spacing, closed cell spray foam, truss spacing, stick frame, insulation, lumber framing, pole barn on July 13, 2023 by admin.

Scissor Trusses, Attaching a Shouse, Attic Truss Space

This week the Pole Barn Guru answers reader questions about possibility of installing scissor trusses in upstate NY where there is a heavy snow load (80psf), a recommendation of whether of not to build a shouse and attach it to an aquaponic greenhouse, what the size of space an attic truss might provide with certain building height restrictions.

DEAR POLE BARN GURU: I am considering building a pole barn in upstate NY. We have a fairly heavy snow load (80psf). I was thinking about getting scissor trusses and spacing them out every 8′ and running purlins on edge. I am struggling to find the answer to whether this is possibly or not. Any help would be great! Thanks. DEVIN in DICKINSON CENTER

DEAR DEVIN: 2020 Building Code of New York State lists Ground Snow Loads (Pg) in Figure 1608.2, with the greatest area being 80 psf with an upwards adjustment of 2 psf for every 100 feet above 1000 feet above sea level. As an alternative, Pg may be determined using ASCE 7.

In most instances, placing columns every 10-12′ with double trusses directly aligned with columns and purlins on edge will be your most economical design solution. Scissor trusses may certainly be provided and used, however usually it will be less expensive to increase wall height to gain headroom.

DEAR POLE BARN GURU: My girlfriend and I are looking to start an aquaponic greenhouse system/farm. We are building a polycarbonate gable style greenhouse 30’x96′-120′ and we are needing to attach a post frame building to the greenhouse in an “l” shape off the shop end. We are/were originally looking to keep the house (4bed/3bath) one level roughly 50×100 splitting the post frame building 50/50 shop and house. But after looking at some of your projects we aren’t opposed to building a taller but shorter home with attached shop still 50×50. My question is in attaching the green house have you ever designed or worked with projects like this? CHRIS in FORT MADISON

DEAR CHRIS: I have not yet attached an aquaponic greenhouse to a post frame building. In all likelihood it can be done, however a question remains as to if it should be done. Aquaponic greenhouses have very high humidity levels (50-70% or more) while living spaces should be 30-50% for health and humidity. It might be prudent to have a small breezeway between, in order to not have to mechanically dehumidify your shop/house space. Otherwise, there is a distinct possibility of having condensation and/or mold/mildew issues within your residential spaces.

DEAR POLE BARN GURU: If I am building a 30×40 with 10 foot side walls, and I can only have a maximum peak of 17 feet, so roughly a 6/12 pitch, if I had attic trusses, how tall would the open space be in the attic room? If I can go taller and have a 8/12, or 9/12 pitch how tall could the open space be in attic? Thanks. KRISTI in SAGINAW

DEAR KRISTI: With an eave height of 10′ and a peak height of 17′ your roof slope would be 5.6/12 If your lower ceiling height was set to a finished 8′ you would have roughly 7′ of height dead center of your attic bonus room space – not tall enough to be considered as a usable room and height would decrease with slope of your roof.

If you were able to get a variance on height, it would obviously increase your space. We typically set a ceiling in bonus attic rooms at 7’6″ above finished floor height. At 8/12 this ceiling height would be roughly feet wide, at 9/12 roughly 10 feet.

This entry was posted in Pole Barn Planning, Trusses, Ventilation, Building Interior, Venues, Pole Barn Questions, Shouse, Pole Barn Design, Constructing a Pole Building and tagged greenhouse, aquaponic greenhouse, purlins, scissor trusses, snow loads, attic truss loft, attic truss on February 8, 2023 by admin.

What to do When the Old Post Frame Garage Has Issues

What to do When the Old Post Frame Garage Has Issues

Welcome back from Tuesday’s posting. As you may recall, when my great-grandfather W.R. McDowell built his two-car Model A garage pre-World War II, it was 16 feet wide by 20 feet deep. This garage was supported by eight cedar poles on minimal footings.

Well….sure enough some of those cedar post footing settled. Some settled more than others, resulting 50 years later in what was appearing to be some sort of carnival fun house. Wood floor parking surface was up and down and the stick framed walls above had developed a serious lean.

By 1946, my great grandparents (W.R. being 74 and Mary Elenis 66) found hiking up and down stairs to be not as much to their liking (much like Mr. Lillequist 10 years before). They sold their cabin to their son Boyd and his wife Jerene.

44 years later, in 1990, Boyd and Jerene had reached their 80s. Having spent my summers at Newman Lake and having developed a strong affinity for it – they gifted this cabin to me, my wife and our young daughter Bailey.

I had recently sold my first business, in Oregon, and returned to Spokane. My intention was to remodel our cabin, so it could become our primary residence. To start with, something had to be done with its garage. Even had it remained structurally sound, while two Model A cars may have fit in it comfortably, we needed more width and depth for two more modern vehicles.

My solution – build a new 22 foot wide by 24 foot deep post frame garage around what was there.

First step was to tear down the old garage to parking deck level.

A couple of trees were too close for comfort and had to be forcibly removed.

Once offending trees were removed, pressure preservative treated posts were set around outside of the existing floor (and a few through holes chainsaw cut through the floor).

After posts were in place, the old floor was removed and framing began. Being it was early December, in Northeast Washington State – we got to deal with snow.

In order to support weight of a concrete slab and vehicles 14 feet above ground, 2×14 #2 Douglas Fir floor joists were placed 12 inches on center, with 2×8 Tongue & Groove decking over top. Raised heel bonus room attic trusses with a 7/12 slope were utilized, in order to allow for a home office space above parking level.

On Super Bowl Sunday Eve of 1991 near tragedy struck our still under construction project. On Friday, our electrician had energized power. When wiring had been run, he had neglected to install protective steel plates at crucial points where sheetrock screws might penetrate wiring. One screw hit a wire in an attic space and smoldered for a day. Around midnight, one of our neighbors got up to get a drink of water and noticed flames coming out of our garage. Their quick thinking and fast response from our local fire department saved this building, with only minimal fire damage, but everything was coated with black soot.

Profuse quantities of Kilz™ were used, however a smoke smell still persisted. We added temperature controlled powered vents in attic spaces, with corresponding air intakes, in order to exhaust burn odors on warm days.

Note: smoke stains on siding above overhead doors and cutouts in endwall for ventilators.

As you may recall – there was some significant grade change at this site. Space below garage floor level, was utilized to create a studio apartment with over 400 square feet of space (current owners rent it out as an AirBNB https://www.airbnb.com/rooms/665906592425731485?source_impression_id=p3_1667315547_%2BXfm5XMqvopowtF%2B).

This entry was posted in Steel Roofing & Siding, Pole Barn Design, About The Pole Barn Guru, Constructing a Pole Building and tagged garage, purlins, floor joists, post frame garage, pressure preservative treated posts, tongue and groove decking, Post-Frame, trusses on November 3, 2022 by admin.

A Post Frame Building at Newman Lake

A Post Frame Building at Newman Lake

In this mid-1980’s photo, from left-to-right are Margaret and Frank Rostead (Frank was best man when my Grandparents were married in 1933), my grandmother Jerene McDowell (b. 1910– d.2006) and a Model A garage built by Grandma Jerene’s father – W.C. McDowell.
Back to our story after some brief history….
Newman Lake is in Northeast Washington State, roughly some 20 miles East Northeast of downtown Spokane and just West of Idaho. It is Eastern Washington’s largest natural lake. Early area inhabitants were Indians who roamed this lake and hillsides for berries and game.
Later traders from Hudson’s Bay company constructed gardens at Newman Lake.
Before 1880’s, each summer, Newman Lake’s shady shores were covered with Indian encampments. Indians picked huckleberries, dried them and made them into pemmican for winter. Camas root was dried and ground into flour. Their main diet was meat – deer, peasant, grouse, rabbit and fish. Venison portions were jerked and dried for winter use.
These Indians returned each summer for many years, after white settlers began moving in.
Slipper Point (named when a white lady lost her slipper at a gathering there) is at an end to a long gradual ridge. Indians used this as a playground and a place to race. One time, at a gathering there, they were having their contests in archery and races. During one race, from ridge top to Slipper Point, a running Indian ran into a partially fallen, slivered and splintered tree.
A long splinter ran him through and killed him. Indians immediately stopped their games and left, thinking evil spirits had placed this splintered tree in their way to chase them away. Those who came back, refused to stay overnight.

William Newman, was from England. At 20, he sailed from Liverpool to New York City in 1858. After having served for five years with US Army’s 9th Infantry, Newman was selected as one of a 25 man Boundary Commission escort, in Washington Territory, where he first saw what later became Newman Lake.

Newman then settled on and farmed an area bordering Newman Lake’s southern portion, until passing in 1887. Just after 1880, white men began homesteading in this area.

Pioneers caught trout in nearby Liberty Lake and transplanted them to Newman. A federal government fish tank railroad car was parked at Moab, on Northern Pacific’s main line. In 1887, residents carried carp to Newman Lake in buckets.
Excursion trains from Spokane ran to Moab, where busses and stages took passengers three miles across split log roads to Newman Lake, where guests could stay at one of four busy hotels.
Early 1900’s found surveyors carving up lake front lots to sell to those wanting to build summer cabins. One such interested party was a Swede – Mr. Swanson. Swanson spent a summer camping in different locations all around Newman Lake. He told his good friend Olof Lilliequist he had found an exact perfect location.
When Swanson went to purchase his lot, he found his friend had purchased every lot along what became known as Swede Bay for $500, including Swanson’s lot. Swanson ended up paying Lillequist $500 for his lot!

Lillequist set out to build his cabin (to be named “Terrace Lodge”), immediately adjacent to his friend Swanson (but higher up his steeply sloped lot). He hired an alcoholic stone mason from Spokane – under a condition of sobriety! In 1909 a flat area was carved out and cornerstones were laid for a 36 foot wide by 20 foot deep cabin. Trenches for two foot thick native stone walls were dug – and stone set starting five feet below grade, with no mortar, and allowed to settle for two years before being grouted in.

Lillequist eventually tired of trips up and down stairs from cabin to beach. He built another cabin– this time shoreline and west of Terrace Lodge. In July 1936, he sold Terrace Lodge to my Great-Grandparents, William C. and Mary Elenis McDowell – grocers in nearby Greenacres.
Here it comes….
Despite a treacherous, winding and steeply sloping dirt access road, McDowell wanted to drive his Model A and park it in a garage when he came to Newman Lake.
A small, flat parking area had been carved out uphill from Terrace Lodge. W.C. poured a concrete wall along this parking area’s downhill, North edge and proceeded to attach a post frame “stilt” garage to it. This two car garage was designed for Model A’s – so was 16 feet wide and 20 feet deep. Eight cedar trees we set on stone pads – two rows of four at 10 and 20 feet from the parking lot. This made for logs from eight to 12 feet in height, due to steep grade!
These logs (poles)were X braced to each other using full dimension, rough, green 2×4 from Eller’s Sawmill. Log tops were trimmed even, and 3 ply rough 2×8 beams were placed from concrete wall, across logs at 10’ to logs at 20’. Three layers of 2×12 decking then ran across beams – at 45 degrees both directions, then straight with building depth on top.
On top of this deck, walls were stick framed, trusses built by hand, 1×4 purlins placed and aluminum roofing was nailed on. Doors were eight foot wide bi-passing sliding barn doors.
These doors had been removed by my youth.
Come back Thursday to find out what happens to our post frame stilt garage.

This entry was posted in Uncategorized and tagged grade, Newman Lake, Terrace Lodge, mortar, stilt garage, decking, Post-Frame, trusses, garage, purlins on November 1, 2022 by admin.

Snow Load, Clear Span Scissor Trusses, and a Window Replacement

This Wednesday the Pole Barn Guru answers reader questions about whether or not a 30 year old building correct snow load, the possibility of clear spanning scissor trusses to eighty feet, and assistance with the replacement (or repair) of a window in a Hansen Building from 2014.

DEAR POLE BARN GURU: How do I figure out the snow load rating for my Morton barn since it is 30 years old and it has poles, trusses and purlins. The purlins are 2 x 8 and 20″ on center with 36 of them over 50 feet and 6 trusses nine feet tall and spanning 50 feet in length and 8 feet apart. Is the rating more than 55psf or not? MARK in PORTVILLE

DEAR MARK: Your roof purlins appear to be adequate to support this type of a snow load. As to trusses, I would reach out to Morton Buildings with your site address and they should be able to pull up truss drawings for your building. If not, you would need to retain services of a Registered Professional Engineer who could do an actual inspection of your trusses and run calculations to determine exactly their capacity.

DEAR POLE BARN GURU: Can you 80 foot clear span scissor truss on a 14-16 foot eave? Commercial shop use. Northern Indiana. ANDREW in AVILLA

DEAR ANDREW: Can and should are not often same.

Yes, an 80 foot clearspan scissor truss can be done, expect it to be either designed with a flat top and a peak “cap” or to be parallel chord with a deep heel and joined together onsite at center. It will prove to be far more economical to utilize flat bottom chord trusses with a taller eave height – this would also allow for full height interior clearance from wall-to-wall. One of our Building Designers will be reaching out to you to further discuss your building needs.

DEAR POLE BARN GURU: I built my Hansen monitor pole barn in 2014. It took this long but a nasty storm broke out my window in the upper floor of the building. What’s the best way to replace a window and frame in a metal sided building. Do I need to remove the surrounding ribbed sheet metal panels and are there any tricks to that? With an eight-year-old build should I use new screws as the gaskets might be dried out from baking on the southern facing wall? Any methods you can suggest to get me going are appreciated. Thanks DAVE in FERNLEY

DEAR DAVE: Unless your window’s vinyl frame was actually damaged, in most instances a glass company can do a repair of just broken glazed portions. I would suggest a call to Capital Glass in Reno (775)324-6688 as this appears to be in their wheelhouse and they service Fernley.

Rarely does glass repair require steel panels to be removed. In an unusual case where there is no alternative, and steel must be taken off, your siding screws have EPDM gaskets. These are UV resistant and have a manufacturer’s warranty they will outlast your steel siding.

Should you have some photos of your completed building, we would greatly appreciate your sharing them with us.

This entry was posted in Pole Barn Questions, Roofing Materials, Constructing a Pole Building, Pole Building How To Guides, Pole Barn Structure, Trusses, Windows, Building Interior and tagged snow load, roof purlins, scissor trusses, clearspan trusses, window repair, window replacement, purlins on September 14, 2022 by admin.

When a Gift Keeps on Giving

When a Gift Keeps on Giving

In our last thrilling installment, our client’s builder was looking at a pile of kindling left after a Christmas Eve windstorm collapsed an under construction 80 foot x 240 foot riding arena.

In this instance, our client’s Christmas morning surprise, was a gift to be repeated.

Original building erector had since been replaced, new trusses and other materials had been built and delivered. Project was moving forward.

Looks nice, doesn’t it (photo below)? First three bays of roof at least partially sheathed with OSB per engineer sealed building plans:

Something mysterious appears to be happening in Bay number four from left end – roof purlins are missing.

Building erector had determined a wall was out of square and removed purlins from this bay, in an attempt to straighten things out. For those of you tuning back in from this building’s prior article, six bays with purlins only have no temporary diagonal braces installed in plane of roof purlins (as detailed in BCSI-B10) and all column bracing has been removed. Note (in photo) top chords of trusses in purlin only areas appear to have a curve between eave and peak.

Once truss chords begin to buckle out of plane, they are difficult, if not impossible, to get back to straight. Rather, they want to continue to buckle, until they result in this:

Hindsight tends to make us all see 20-20. Had temporary bracing procedures of BCSI-B10 been followed chances are more than good we would not be looking at this photo. Fully sheathed, those first three bays of roof, would have provided a significantly stiff anchorage for balance of roof – had purlins in bay #4 not been removed.

On a happy note, the third time was a charm, building was successfully completed – without further incident.

This entry was posted in Roofing Materials, Trusses, Budget, Columns, Horse Riding Arena, Pole Barn Design and tagged roof sheathed with OSB, purlins, BCSI-B10, truss chords, temporary diagonal braces, column bracing, roof buckling on July 12, 2022 by admin.

My Drill Stem Pipe Barn Sways in Light Winds

“Recently my husband and I decided we would try building a pole shed row barn for our horses out of structural drill stem pipe. We used 2 7/8 pipe columns on 12’ centers with 2 3/8 pipe columns supporting the (over hang, non-stall) side of the barn. It is 60×24, with 12’ tall center poles and 10’ tall short walls. The rafters are welded 2 3/8 pipe with 6” clips with the 2×6 purlins bolted to them with hex bolts to support the 26g r panel roof. We ended up putting the columns (poles) 3’ in the ground with 1 (and some of them got 2) bags of concrete in the hole with the remaining dirt backfilled. We also had the pad built up after the poles were set so there is about a foot of sand as well. The poles all have a base of red clay. We didn’t know what we were doing so we ended up not doing any footers or anything like that. So my question is, is this sufficient for the columns and if not how do we add support after they’re already up? My concern is this thing falling on our horses. We have significant movement (in my opinion) and racking so far, even after putting the roof on; however, it did get better after the roof went on. I can still shake it if I go to swinging on one of the columns. We can also we some cracking in the ground around the poles when it goes to moving after we’ve been pushing on it. There are no walls on yet, but we plan on adding a wall on each end and possibly the whole backside of the barn where the stalls will go. The front will stay open. Stalls will be welded to the vertical columns using 2 7/8 pipe so the entire structure will end up being held together at the base like it is at the top. I just worry about it buckling somewhere and coming down because we didn’t put our poles in the ground good enough. Please let me know your thoughts and what we can do to provide more strength. I’ll send some pictures so you can understand what I’m talking about. Thanks for any advice 🙏

I will add, we had around 25mph wind gusts today and I did notice it swaying and vibrating some but I wouldn’t have been able to tell if I hadn’t of leaned against one of the poles.”

Many thanks,

Bethany

Thank you for reaching out to me. Your building has a plethora of challenges, some can be solved, others you will have to make do with best you can.

Although not a current challenge, building upon a red clay base is likely to result in some long term negative consequences. Why would clay be an issue to build upon? Clay expands and contracts depending upon the amount of moisture present. When wet – clay expands, when dry it shrinks. These movements will cause buildings to move as well – not a good thing.

If your intent is for your building to be a permanent long-term structure, my best recommendation is to engage the services of a Registered Professional Engineer who can make recommendations as to how to properly reinforce what you have to make it structurally sound.

Issues include (but may not be limited to):

Lack of adequate concrete backfill/encasement under and around vertical pipes. This can be tackled by digging out around each column down to where you have current concrete and backfilling with more pre-mix. Required diameter can be determined by whomever you hire as an engineer.

Pipe columns may be inadequate in diameter for proper stiffness.

Adding properly engineered walls will increase stiffness. Should you happen to enclose your two ends and a single sidewall, your resultant will be a three sided building and they have an entire set of challenges all their own (for extended reading: https://www.hansenpolebuildings.com/2014/03/three-sided-building/).

This entry was posted in Columns, Pole Barn holes, Pole Barn Questions, Pole Barn Design, Pole Barn Structure and tagged purlins, Rafters, drill stem pipe, stem pipe, 2 7/8 pipe, hex bolts, red clay, building racking on February 15, 2022 by admin.

4×4 or Double 2×4 Bay Roof Purlins?

4×4 or Double 2×4 for 12’ Bay Roof Purlins?

Reader JOHN in HUNTSVILLE writes:

“If you have trusses spaced at 12 feet, can a 4x4x12 or two 2x4x12’s span the distance given the minimal snow loads in Arkansas? I know this is question #2 but what kind of joist hangers do you use (Simpson Number or equivalent) for purlin attachment to trusses?”

We typically would use 2×6 #2 on edge for these recessed (between truss pairs) roof purlins. Here are the calculations:

Assumptions:

Roof slope = 4:12 (18.435° roof angle)
Trusses spaced 12-ft. o.c.
Purlin span = 11.75-ft.
Purlin spacing = 24 in.
Purlin size 2″ x 6″ #2
Roof steel dead load = 0.63 psf steel American Building Components catalogue
Roof lumber dead load = 62.4 pcf * 0.55 lbs/ft.3 / (1 + 0.55 lbs/ft.3 * 0.009 * 0.19) * (1 + 0.0019) * 1.5″ / 12 in./ft. * 5.5″ / 12 in./ft. * (12′ – 3″ / 12 in./ft.) / 12′ / (24″ / 12 in./ft.) psf in purlin weight based on 0.55 G NDS = 0.963 psf
Total purlin dead load = 1.593 psf
Check for gravity loads

Bending Stresses

Fb: allowable bending pressure
Fb‘ = Fb * CD * CM * Ct * CL * CF * Cfu * Ci * Cr
CD: load duration factor
CD = 1.25 NDS 2.3.2
CM: wet service factor
CM = 1 because purlins are protected from moisture by roof
Ct: temperature factor
Ct = 1 NDS 2.3.3
CL: beam stability factor
CL = 1 NDS 4.4.1
CF: size factor
CF = 1 (not applicable to SYP)
Cfu: flat use factor
Cfu = 1 NDS Supplement table 4A
Ci: incising factor
Ci = 1 NDS 4.3.8
Cr: repetitive member factor
Cr = 1.15 NDS 4.3.9
Fb =1000 psi NDS Supplement Table 4-A
Fb‘ = 1000 psi * 1.25 * 1 * 1 * 1 * 1 * 1 * 1 * 1.15
Fb‘ = 1437.5 psi

fb: bending stress from roof live/dead loads
fb = (purlin_dead_load + Lr) * spacing / 12 * cos(θ) / 12 * (sf * 12 – 3)2 / 8 * 6 / b / d2 * cos(θ)
Lr = 20 psf using the appropriate load calculated above
fb = 21.593 psf * 24″ / 12 in./ft. * cos(18.435) / 12 in./ft. * (12′ * 12 in./ft. – 3″)2 / 8 * 6 / 1.5″ / 5.5″2 * cos(18.435)
fb = 1060 psi ≤ 1437.5 psi; stressed to 73.7 %

Deflection

Δallow: allowable deflection
Δallow = l / 180 IBC table 1604.3
l = 141″
Δallow = 141″ / 180
Δallow = 0.783″
Δmax: maximum deflection
Δmax = 5 * Lr * spacing * cos(θ * π / 180) * (sf * 12 – 3)4 / 384 / E / I from http://www.awc.org/pdf/DA6-BeamFormulas.pdf p.4
E: Modulus of Elasticity
E = 1400000 psi NDS Supplement
I: moment of inertia
I = b * d3 / 12
I = 1.5″ * 5.5″3 / 12
I = 20.796875 in.4
Δmax = 5 * 20 psf / 144 psi/psf * 24″ * cos(18.435° * 3.14159 / 180) * (12′ * 12 in./ft. – 3″)4 / 384 / 1400000 psi / 20.796875 in.4
Δmax = 0.559″ ≤ 0.783″

2×4 #2 and 4×4 #2 Southern Pine have Fb values of 1100

Sm (Section Modulus) of a 2×6 is 7.5625; (2) 2×4 nailed together would be 1.5″ width x 3.5″ depth^2 x 2 members = 6.125 I would = 10.71875; 4×4 would be 7.146 with I = 12.5052

The (2) 2×4 would be stressed to 82.7% in bending however Δmax = 1.085″ so would fail due to being over deflection limits

How about a 4×4? 70.9% in bending Δmax = 0.9296″ so would also fail due to being over deflection limits

For our 2×6 purlins, we specify a Simpson LU26

This entry was posted in Pole Barn Structure, Trusses, Pole Barn Questions, Pole Barn Design, Pole Building How To Guides and tagged ground snow load, purlins, snow load, Simpson brackets, roof snow load, trusses on February 10, 2022 by admin.

How to Fix Many Leaks on a New Steel Roof

How to Fix MANY Leaks on a New Steel Roof

Reader GUY in SHELTON is probably wishing he would have ordered a new Hansen Pole Building right now. He writes:

“Best way to fix MANY roof leaks on a guaranteed newly built pole barn with metal roof over 2-inch vinyl glass woven insulation. Purlins are on 2 feet centers with no underlayment. Thank you.”

Mike the Pole Barn Guru advises:

Sadly this makes my case for why clients should do their installations, as rarely do we ever find an instance of a D-I-Yer having roof leaks.

You need to put whomever installed your building on notice, following whatever procedure is outlined in your written contract with them. If there is no procedure outlined, send a certified letter, return receipt requested, to them, demanding prompt repair or replacement of leaking roof panels, as well as any metal building insulation underneath. Steel panels should never be installed over damp insulation, as this moisture can cause premature deterioration of panels and void steel manufacturer’s warranty. You might want to include that the repaired roof must be inspected by a representative of whomever manufactured your building’s steel panels and require them to sign off as to repair having been done adequately, so steel panel warranty is not compromised. You will want to pay careful attention to time frames, as Washington State only requires registered contractors to offer a one year warranty on materials and labor. Should you not get a prompt correction, you need to file a claim against their Contractor’s Bond (you may want to do this anyhow, as chances are you are not the only person this builder has done poor work for, and claims are paid in order filed). It may also behoove you to engage an attorney who specializes in construction law.

If a “random miss” occurs, repair is to have someone hold a wood block underneath the hole and drive a screw through the hole into the block. This is the manufacturer’s only approved repair for a missed screw.

Do NOT, under any circumstance, attempt to fix a missed screw hole with caulking.

Here is a short story about how I handled a similar situation, back when I was a builder: https://www.hansenpolebuildings.com/2014/09/omsi/

This entry was posted in About The Pole Barn Guru, Roofing Materials, Pole Barn Questions and tagged metal roof, metal building insulation, purlins, glass woven insulation, contractors bond on January 20, 2022 by admin.

Help! My Barndominium Roof is Dripping!

Help! My Barndominium Roof Is Dripping!

Reader TIMM in WHITEFISH writes:

“Thanks for taking my question. I recently built a barndominium in NW Montana. I tried to find someone to build it for me, but the demand and cost in the area had gone up so much that I had to do almost all the work on my own. I was not completely unfamiliar with building but not an expert by any means but I was able to get it built with helpful videos found online. I finished the home in late October and have moved in. The home is 28’x36′ with 10′ walls and is all living space, no garage. I had planned on doing spray foam insulation around the entire shell of the barn and had hired a company in August to come out and spray the barn but they were not going to be able to get to the building until December at the earliest but we were willing to do it and fight through the winter in our camper. Our plumber mentioned a product to us that he had seen some other clients use called Prodex that had similar characteristics of spray foam with a reflective surface on both sides and it was something I could do myself and much sooner. I did some research and the product looked good and the reviews looked good so I bought some and installed it. The steel was already on when I installed it so the Prodex was installed by stapling or screwing to the Purlins/Girts around the whole building which was an install method on their website. While we were mudding/painting/texturing I noticed some condensation in the attic in between the steel and the Prodex insulation (I could see where it was coming through a seam in the Prodex). I asked some people and they thought it was just because I was putting a lot of moisture in the air that was causing the condensation and it would dry out when we were done. On a recent trip up to the attic I noticed that the steel is still condensating when it is cold outside and the Prodex itself seems to be condensating as well. I emailed Prodex and they told me that it is caused by cold air moving across the inside surface of the steel and I should put foam around the ridge cap, eave edge of roof and tops of wall. I have foam around the ridge cap, but nothing on the ridge cap ends, I have foam on the eave edge of the roof, but only in the high ridge parts, and I have nothing on the walls. I am also concerned that this is happening inside of the walls which may lead to a bad mold problem next summer. My question is, how do I get it to stop condensating? I am ready to do whatever I need to do. I just don’t want to throw ideas at the house until something works. As far as ventilation goes, I am sure I do not have enough but was hoping to address that in the summer months. I do not have eaves on the building which I regret so my only real ventilation is the ridge cap and the little bit that may be coming through the ridges on the eave edge of the roof. I thought about gable vents, but I felt like that would let too much cold air in and would make the issue worse, but maybe that is what I need? If I put in gable vents, do I pull out the Prodex insulation and leave bare metal on the inside of the attic? I am trying to figure out a way to reduce the moisture right away (dehumidifier?) while I work on a long term solution but I don’t know which direction to go to solve this issue. I thought about pulling off the steel and putting in plywood sheeting, but we are in the middle of winter and that would have to wait until Spring at least and I am afraid I will end up with too much water damage by then. I have even considered putting sheeting under the roof and replacing the outside walls with wood siding but the cost would be high and I feel like there should be a solution to this issue. For heat we electric wall heaters (Cadet in-set wall units) occasionally and a pellet stove most of the time. We put the Prodex insulation as well as blown insulation in the attic to about 12 inches deep and we put Prodex as well as rolled insulation in the walls for a total of about an R30 value. Dryer and bathroom vents both go outside and nothing is venting into the attic. Any help would be appreciated! Thanks.”

Mike the Pole Barn Guru says:

Kudos to you for doing a D-I-Y. Sadly you were lead to a product (Prodex) claiming to be insulation, however in reality it is a condensation control, and only if totally sealed.

All of these issues could have been easily addressed at time of construction had your building kit provider given you proper advice.

First thing to do is to get your attic properly ventilated – you need to add at least 121 square inches of NFVA (Net Free Ventilating Area) to each gable end. This will give you an air intake and your vented ridge will then function as a proper exhaust. By itself, this should greatly minimize, if not totally cure your problems.

Pole Barn Guru Blog As time allows, remove roof Prodex, have two inches of closed cell spray foam applied to roof steel underside, and increase thickness of blown in attic insulation to R-60.

If you do not have a well-sealed vapor barrier under your concrete floor, if possible, seal top side of it (this is where moisture is coming from).

Heating as much as possible with your pellet stove will also help to dry your interior air out and provided your slab is sealed, should help greatly.

I do have some concerns about your walls, if you have faced insulation batts with Prodex on outside of batts, you are potentially trapping moisture between two vapor barriers. If this is indeed your case, come Spring, remove siding (one wall at a time) , remove Prodex (as much as possible) and add a Weather Resistant Barrier (Tyvek or similar) to the exterior of framing, properly seal all wall openings and reinstall wall steel.

This entry was posted in Insulation, Pole Barn Heating, Pole Barn Questions, Roofing Materials, Barndominium, Ventilation and tagged gable vents, Prodex, spray foam insulation, Ridge cap, vapor barrier, barndominiums, condensation, net free ventilation area, eaves, girts, NFVA, purlins on December 16, 2021 by admin.

Cabin Insulation Follow Up

Cabin Insulation Follow Up

First Winter Heating Bill

Mike’s loyal readers may recall that I was privileged to be able to write several blog articles on the development of my plans to build my fishing cabin.

https://www.hansenpolebuildings.com/2019/03/development-of-my-cabin-plans/

https://www.hansenpolebuildings.com/2019/03/pole-barn-cabin-part-ii/

https://www.hansenpolebuildings.com/2019/03/participating-in-ricks-post-frame-cabin-planning/

https://www.hansenpolebuildings.com/2019/04/my-pole-barn-cabin-part-iii/

https://www.hansenpolebuildings.com/2020/10/my-fishing-cabin-is-finished/

During my time as a Building Designer, I strongly emphasized to all of my clients that they should have an insulation plan for their building BEFORE they order the building! The reason being that any design elements for the insulation, such as 2×8 walls or 2×10 roof purlins can be designed prior to ordering.

One of the blogs went into detailed information on how I insulated the building in which I said tongue in cheek that the winter will tell the tale of how well it worked. For that reason, I thought that I’d send in the “Paul Harvey” version.

This link tells you how and why I insulated it the way that I did, with pictures:

https://www.hansenpolebuildings.com/2020/06/fishing-cabin-insulation/

Now for the rest of the story

On December 15th, 2020 I had the LP company top off my tank a little extra. My driveway is 700 feet and I did not intend to plow it and wanted to be sure that there was ample gas to get through the winter. They filled it to 92%.

They did not refill the tank until 7-20 21. They filled it from 62% to 80%! It only took from 92% down to 62% to heat the building ALL winter!

I would leave the thermostat set at about 50 degrees and when I would come out, the in-floor heat would have a hard time getting the building warm. No problem. The wood burning stove would get the temperature up to 70 in less than two hours and the in-floor heating would keep it there.

All in all, I am very happy about it! Less than $200 to heat for the whole winter and it got cold!

When planning your building be sure to have the insulation plan prior to ordering the building!

This entry was posted in Uncategorized and tagged 2x10 roof purlins, wood burning stove, insulation, girts, purlins, in-floor heat, fishing cabin, 2x8 walls on September 1, 2021 by admin.

Steeply Sloped Post Frame Roofs

With fully engineered post frame buildings becoming a popular barndominium design solution, future home owners are looking for more variety in their builds.

Loyal reader KEITH in MADISON is one of these and writes:

“Thanks very much for all the work you do to make this website such a treasure trove of information!

Online, I see almost exclusively 4/12 pitch post frame trusses, even on residential builds. Why is that? Is it possible to have, say, a 12/12 pitch roof with all the existing benefits of post-frame (ease of construction, affordability, engineered trusses, etc.)?”

Mike the Pole Barn Guru writes:
Thank you for your kind words, they are appreciated!
In most instances a 4/12 slope is a least expensive design solution. Lesser slopes require larger or higher graded members and pressed steel connector plates, steeper slopes often allow for smaller components, however they are greater in length and at a certain point cause challenges in fabrication and shipping. Many truss manufacturers are limited to trusses with a 12 foot overall height, due to their equipment. Taller trusses can require a piggyback (or cap) to create requested profiles. As slope increases, more roof purlins are needed and both roof and endwall steel lengths increase.

A consideration many miss – is design of wall columns is impacted by them having to carry wind against roof surfaces. As your roof grows in height, loads can increase significantly (but not prohibitively expensively).

By maintaining a single slope for an option, makes for pricing very simple for providers lacking in sophisticated engineering design and pricing software.

With all of this said, our system can do any slope you desire – even down to fractions of a degree of slope. My own personal first post frame shouse (shop/house) was done with 7/12 slope trusses to match an existing cabin on our property. Currently, we live in a post frame barndominium using gambrel trusses where slopes are 6/12 and 24/12. When it comes down to it – if you can dream it, chances are excellent we can provide a structurally sound design solution for your new building.

This entry was posted in Barndominium, Pole Barn Questions, Shouse, Pole Barn Design, About The Pole Barn Guru, Roofing Materials, Pole Barn Planning, Trusses, Post Frame Home and tagged 4/12 roof slope, 12/12 roof slope, trusses, purlins, steel connector plates on January 14, 2021 by admin.

Steel Roofing and Siding Over Purlins

There is just plain a lot of bad (and scary) information floating around out there on the internet. For whatever reason, people will believe a random unqualified answer from a stranger, rather than going to a highly educated expert (e.g. Registered Professional Engineer).

Reader DYLAN in BEDFORD writes:

“I am building a 50×60 using 2×6 stud frame walls. Trusses 4’OC. The garage area (30×60) will have around 12’ceiling. The living area (20×60) will go back and stick build ceiling rafters 2’OC to make 8’ceilings. 12’ ceiling on the living area is just more to heat and cool – not necessary. My builder right now plans on putting 2×4 purlins and 2×4 girts on roof and side walls. Then wrap the whole thing with tyvek and out metal on.

My question starts with is this ok?

Should I consider plywood/osb on the roof or walls in lieu of 2×4 purlins/girts?

Are 4’oc trusses ok if I am going back to the living area and building ceilings 2’oc?

Are 2’oc rafters ok assuming I finish the ceiling with 5/8” drywall or wood tongue groove or similar?

I will probably spray foam insulation in the living area. This should help with noise during rain on the metal roof.”

Mike the Pole Barn Guru responds:

My recommendation would have been for you to erect a fully engineered post frame building, rather than spending tens of thousands of extra dollars in an attempt to make a stick framed house look like a pole building.

Ultimately how your building is assembled structurally should be up to whatever engineer you (or your builder) hire to provide your home’s engineered plans. Building Codes do not allow for stick framed walls taller than 11’7″ without engineering, so you should be there already.

Steel panels should not ever be screwed into OSB only and even plywood only would only be on roofs if you are using a standing seam (concealed fastener) steel. I (and most likely your engineer) will specify 2×4 or even 2×6 girts and/or purlins in order to provide a proper surface to screw steel panels to. Your trusses every four feet may be adequate in your living area, it will depend upon how your engineer designs structural attachment of your furred down ceiling, as well as weight supported by it. Rafters 24 inches on center will provide sufficient support for 5/8″ drywall.

You should not place Tyvek between roof framing and roof steel – as Weather Resistant Barriers (WRB) allow moisture to pass through. This could allow condensation to be trapped between your home’s WRB and roof steel, causing premature deterioration.

This entry was posted in Professional Engineer, Pole Barn Questions, Pole Barn Design, Pole Barn Homes, Building Department, Constructing a Pole Building, Pole Barn Planning and tagged furred down ceiling, girts, purlins, tyvek, spray foam insulation, weather resistant barriers, OSB, plywood, post frame building, stick built, registered design professional on August 27, 2020 by admin.

Why You Should Install Post Frame Roofing Before the Walls

Over roughly 40 years of post frame construction, I have seen photos of one or two (or perhaps thousands) of post frame buildings under construction. I can pretty well tell from these photos if those doing assembly are (or were) stick builders.

I grew up as a framing contractor’s son (and later working for dad and my uncles stick framing), where we built walls with sheeting (and often siding) on them and tipped them up into place. This is all fine and dandy for ‘conventional’ stick frame construction, however not necessarily easiest or best when it comes to post frame.

In post frame construction, trusses extend from column outside to column outside (plus any overhangs). If walls have been framed (girts, headers and door jambs placed) trusses will have to be jockeyed around to be lifted in place from inside the building. This is especially true in applications with bookshelf (inset) style wall girts.

Most post frame buildings have one or more columns out of perfect placement along building length. Accept it, this is just going to happen no matter how perfect you or your builder might be. Most buildings have a far greater roof purlin quantity per bay, than wall girts per bay. By framing the roof first, all purlins (assuming they are inset) can be cut to the same length in each bay, this is determined by engineered plan column spacing, less truss assembly thickness. When trusses are in place, column tops will easily move forward or backwards so all truss supporting columns end up spaced per plans. This also aids in an overall building roof length creation matching expectations.

During the truss placement process (regardless of method used) there will come times when it is highly convenient to be able to walk ‘through’ a wall. Girts in place means having to fit through girts or walk around – either of which slowing construction processes.

It is far easier to square up the roof without wall framing member resistance. Once roof sheathing or roof steel is in place, it makes it simpler to plumb building corners.

With roofing in place and walls open, a concrete slab may be installed if desired. This helps protect concrete pour from weather elements, especially heat in summer or rain. Pre-mix trucks can access and chute through any accsessible sides or ends. This can eliminate the need to pay for a pump truck.

Want your new post frame building as perfect as possible and completed quickest? Then roof first, walls after is most probably your route to success.

This entry was posted in Uncategorized and tagged wall girts, purlins, stick frame construction, plumb building corners, trusses, post frame buildings, bookshelf girts on August 19, 2020 by admin.

Truss Spacing and Design

Truss Spacing and Design for Sheathed Post Frame Roofs

In most instances, there is not a structural or Code requirement for solid roof sheathing (plywood or OSB – Oriented Strand Board) to be placed below through screwed roof steel for post frame buildings. In some cases, clients look upon this as being an easier installation when doing a DIY build. For others, it is about providing a thermal break to eliminate underside of roof steel condensation. And a few look towards minimization of potential hail damage.

Reader CARROLL in PORTER writes:

“ Wanting to build Pole Barn that is about 35’x80’x12′ My question is, if I want to install 1/2″ decking plywood or OSB decking with underlayment and metal panels how far apart will I need the trusses to be center to center or what kind of truss design will I need? I guess it could be a 4/12 or 5/12 pitch if that helps any.”

Provided you have adequate available space, you may want to tweak your footprint dimensions in order to optimize your return for your investment. As steel comes in three foot widths and lumber in two foot lengths, your most cost effective dimensions of length and width will be multiples of six feet. In your instance, I would recommend 36 feet wide and 84 feet long.

With this said, I would place a single truss on each endwall and a two ply truss every 12 feet to align with your sidewall columns. Purlins can be placed on edge, using engineered steel joist hangers, between each set of trusses and spaced every two feet to support your sheathing. Whether plywood or OSB, panels are best installed running up roof from eave to ridge (perpendicular to purlins, parallel with truss spans). If not using synthetic underlayment, you should use 30# asphalt impregnated paper (roofing felt). With Hansen Pole Buildings, we purposefully design all trusses spanning 40 feet or less with a greater than minimum requirement top chord dead load – in order to accommodate those who want to install solid sheathing.

This entry was posted in Pole Barn Questions, Pole Barn Design, Roofing Materials, Pole Barn Planning, Trusses and tagged roof sheathing, OSB, top chord dead load, roofing felt, 30# asphalt impregnated paper, 1/2" decking, 1/2" plywood, truss spacing, purlins on July 23, 2020 by admin.

Post Frame Purlin Blocking

Every time I begin to rest on my laurels and think I have covered all post frame (pole barn) building basics up jumps yet another one to bite me where I deserve to be bitten due to my overlooking it.

Our independent drafting team at Hansen Pole Buildings (thanks Kristie) came up with this question recently.

“As we are building our building, a question came up: what is the reason for purlin blocking? Why do we need it? What’s the important purpose for it? We will be doing this step tomorrow and actually considered skipping it (sorry, bad of us I know). Is this all explained in the CM, because I have looked and couldn’t find the why’s. I bet ALOT of people skip this step and just wanted to see why we have it.”

Well, our 500 page Construction Assembly Manual covers lots of “how tos” and very few “whys”. Biggest reason is we would hate to make it into a 700 or 800 page manual. We try to cover it all and continually add to it and improve it, so every time we get a question not covered by it, we add more information. Even though these subjects do not make a dime for Hansen Pole Buildings, we have recently expanded sections on Site Preparation and Concrete Floors. It is all part of us delivering “The Ultimate Post Frame Building Experience™” https://www.hansenpolebuildings.com/2019/05/the-ultimate-post-frame-building-experience-2/

Back on task – I will preface this by letting you readers know Kristie and her husband are currently erecting their own Hansen Pole Building.

There exist two types of purlin blocking:

At endwalls (this is Kristie’s case) – Building Codes require airflow from vented soffit on gables overhangs be blocked off. Ventilation for dead attic spaces must be accomplished by either a combination of eave and ridge vents or by gable vents. Venting through end overhangs will disrupt airflow for a properly ventilated attic space.

Structurally a solid load path must be provided in any building to transfer wind shear loads from roofing to ground. Purlins overhanging an end truss and attaching with a hanger such as a Simpson H-1 do not accomplish this. Brackets will not prevent purlin rotation under extreme loads. Properly placed, endwall overhang soffit panels can be attached to these same blocks, as they serve a plethora of duties.

Purlin blocking can also be “mid-span” – when a 2×10 or larger member (girt, purlin, floor joist, etc.) is 2×10 or greater mid-span blocking is required if a member is unsupported for more than eight feet.

There you have it and if you win on Jeopardy thanks to this, I will work for a percentage.

This entry was posted in Pole Barn Questions, Pole Barn Design, Building Overhangs, Pole Barn Structure and tagged purlin blocking, endwall purlin blocking, attic spaces, post frame building, purlins, vented soffit, the ultimate post frame building experience, wind shear loads on April 23, 2020 by admin.

Another Post Frame Builder Blunder

In our last exciting installment of “As The Builder Burns” I shared a photo of a prefabricated end truss deeply in need of a sky hook in order to remain suspended in space.

Today, it gets even better, with this very same builder showing off his ability to pretty well completely ignore engineered building plans, not to mention not considering opening our Construction Manual.

A typical Hansen Pole Building has widely spaced columns – most often every 10 or 12 feet, with ganged trusses (in this case three ply due to 60 foot width clearspan and a large snow load). Between those ganged trusses, on edge and attached with joist hangers, would be purlins.

I admit, I had to look long and hard at this photo to believe it. I would look away, ponder it, then look back again.

It wouldn’t go away. This is bad, very, very bad indeed.

My first thought was how did they ever get roofing on without those flatwise purlins buckling under an installer’s weight? You could not have paid me enough to have risked my life on this roof!

Now I do have to admit having 5-1/2 inches of width to drive a screw in makes for a very large and inviting target. Chances are good no purlins were missed with screws.

On every other purlin, they did make an attempt to stiffen things up by forming a “T”, with one purlin vertical and one flat on top of it. Even if combined Section Moduli of these two members would make them adequate to carry a load from four feet of roof (because unreinforced purlins laid flat epically fail, so “T”s have to carry all roof loads), vertical “web” of these “T” purlins would need to be supported at each end by joist hangers. As placed, under a load, deflection will cause nails joining these two members to withdraw from the vertical member causing yet another failure point.

Of course all of this has left me wondering….what did this builder think all of those boxes of joist hangers were for?

This entry was posted in Pole Barn Design, Steel Roofing & Siding, Building Contractor and tagged Section Moduli, roof deflection, purlins, clearspan on April 15, 2020 by admin.

Commercial Post Frame Building Blunder

My Facebook friend Dan recently commented upon this article https://www.hansenpolebuildings.com/2020/03/there-is-a-right-way-and-this-way/ wanting to know if I could show some other building blunders.

Yes Dan, I can.

As Technical Director for Hansen Pole Buildings since 2002, I have gotten to assist a few DIYers and post frame builders with their building questions. DIYers are generally fabulous, and their stories usually begin with something similar to this:

“I have made a mistake worse than anything you possibly ever seen, can you help me?”

To them my response is most usually, “As a post frame building contractor, I ran as many as 35 crews in six states. If something could be done wrong, they probably did it, so how can I assist you?”

Most builders usually take a different tack, “Your plans are stupid and your engineer is an idiot!”

And from me, “Now we have this settled, describe your challenge and we can work towards a solution.”

Please keep in mind, our third-party engineer sealed blueprints are similar whether for a builder or someone doing DIY. We are not picking specifically upon builders by giving them less to work from.

In this particular instance, an allegedly professional builder has found a way to go above and beyond any bad I have ever previously experienced.

Far beyond.

This article’s photo shows a 60 foot span prefabricated roof truss, somehow hanging in air two feet past a building endwall. Builder contacted us because he was “short” on trim. From this picture, I am guessing trim is not all he is short on.

This truss was supposed to be notched into the corner and endwall columns by 1-1/2 inches, so it has full bearing at each point. Horizontal 2×4 framing (shown as being cut to fit between end truss webs) was to have been placed upon the end truss face to attach steel siding. Roof purlins, on edge, were to go across top of this truss to support a two foot overhang. Engineered Simpson brackets were provided to attach purlins to truss and solid blocking was to be placed between overhanging purlins above the truss.

I am totally baffled as to what is supporting this truss, or how the builder believed this was going to be correct. Certainly he did not look at building plans or open our Construction Manual. This is one of several pretty much unbelievable FUBARs on this building – and it resulted in my making a recommendation to dig a deep trench at one end of the building and bulldoze everything into it!

This entry was posted in Columns, Pole Barn Design, About The Pole Barn Guru, Building Overhangs, Constructing a Pole Building, Building Contractor, Trusses and tagged purlins, Simpson brackets, builder, endwall overhang, end truss on April 14, 2020 by admin.

Hi, I Should be an Engineer

Hi, I Should Be an Engineer. Can You Tell Me What I Left Out?

Seemingly every Spring I receive an email similar to this one from JOHN in UNION DALE, who it sadly appears has not done much (if any) homework in reading my articles.

JOHN writes:

“ Hi, I have been doing a couple of months homework on making my pole barn, my plan is a 30×50. Right now my plan is using (16) 6x6x16 pole about 52 inches in the ground, the spacing between posts will be 10 ft, now I have not decided on a concrete cookie before the setting the post or gravel first has a drainage layer the set the pole and then use about 5 bags of concrete for uplift protection and the normal back fill, for the posts I got post protectors, so the wood is separated from the soil, my plan is to use double 2×12 for the top strapping with the posts notched at the top for added snow load, has far has the roof it will either be a 4/12 or 5/12 pitch my plan is using 2×6 rafters that I’m making on the ground and hoisting up by myself and they will be on 48 inch on center, my purlins are going to be 2x4s about 2ft apart and standard metal to finish it off, if you can can you please let me know if I left anything out, thanks ps I forgot to say the door opening on a non-load bearing wall will be a 12ft wide and 10ft tall, I’m thinking about putting a door on a load bearing wall a 10ft, all doors are going to be sliding barn doors.”

Mike the Pole Barn Guru Responds:

Well John, you have left out a crucial part. One no proper pole barn should be without. Plans designed and sealed by a Registered Professional Engineer specific to your building at your site. To build without them is, in my humble opinion, fool hardy and I cannot endorse your plan of attack or methods of construction without them. Outside of this – attempting to field construct your own roof trusses is not a good choice. Prefabricated trusses are truly a bargain, especially when considering risks involved should your home made trusses collapse injuring or worse killing you or a loved one.

For last year’s related article, please read: https://www.hansenpolebuildings.com/2019/05/self-designed-pole-buildings/

For extended reading on the misadventures of site built roof trusses: https://www.hansenpolebuildings.com/2018/12/site-built-roof-trusses/

This entry was posted in Pole Barn Design, Roofing Materials, Constructing a Pole Building, Pole Barn holes, Pole Barn Planning, Shouse, Pole Barn Structure, Trusses, Concrete Cookie, Pole Barn Questions and tagged concrete cookie, Uplift, roof trusses, purlins, post protectors, snow load on April 1, 2020 by admin.

Winch Boxes- A Post Frame Miracle

Winch Boxes – a Post Frame Miracle

Back in my M & W Building Supply days we had provided a pole barn kit package to a client in Woodburn, Oregon. One of Jim Betonte’s Farmland Structures post frame building crews was doing erection in our client’s back yard. Our office received a hostile phone call from this client about lunch time. He had come home to get a bite to eat and found his new building’s roof all framed up.

And on the ground.

And he was less than happy…..okay he was pissed off.

He was furious because he did not want heavy equipment, like a crane, run across his yard to lift his roof up. Luckily we were able to talk him down and assured him when he came home from work his roof would be up in place and there would be no tire tracks.

True to our word, when he came home, his roof was up, there were no tire tracks and he wanted to know how we did it.

Jim’s crew refused to tell him!

Our office wouldn’t either!

We were having way too much fun at our client’s expense. He was pretty sure we had used a helicopter, he even asked his neighbors if they had heard anything unusual.

Nope.

In much of our country, post frame buildings are constructed with a truss or trusses aligned directly with building’s sidewall columns. Purlins (generally and hopefully) on edge span distances between trusses.

I will share with you this miracle (in pictures) eventually. But first, a few words about my friend who has provided these photos.

Stay tuned to this station for our next exciting installment (and those promised photos).

This entry was posted in Pole Barn Design, About The Pole Barn Guru, Constructing a Pole Building, Trusses and tagged trusses, purlins, winch boxes, M&W Building Supply on October 31, 2019 by admin.

An Avoidable Building Failure

I had already begun working on this article when I saw on Facebook a great post frame prefabricated wood roof truss setting video (https://www.facebook.com/ruralrenovators/videos/2443278165738995/) posted by Kyle Stumpenhorst of Rural Renovators, LLC (https://rrbuildings.com/).

This is not a paid endorsement for Kyle – however I do believe Kyle really cares about doing a job right. If I personally lived in his immediate service area of Franklin Grove, IL and needed a post frame building erected, I would call Kyle – and wouldn’t ask for bids from anyone else. I am willing to pay for someone who truly takes pride in what they do.

Photo above and excerpts in italics are from a July 29 updated posting at www.fox9.com (for full article: http://www.fox9.com/news/widespread-damage-east-of-twin-cities-after-tornado-reports).

Areas east of the Twin Cities were among the hardest hits spots after storms ripped through Minnesota and Wisconsin on Sunday.

There were at least four reports of tornadoes created by the storms across Minnesota — including one near the area of Scandia — but none have been officially confirmed by the National Weather Service as of Sunday night.

Daniel Kaiser said, “In probably 15, 20, 25 seconds, it was kind of in and out of here so that wind, it didn’t really last too long. I was just kind of amazed to see all of the trees down from the wind we had here.”

Several decades of old trees lay across Daniel Kaiser’s lawn in Scandia. He’s also dealing with some unusual debris.

“That’s one of the solar panels from across the street,” he explains. “It’s amazing how much force that must have been coming through here carrying these things because they aren’t light.”
One solar panel ended up stuck several feet off the ground in a tree. Onlookers were surprised by the damage.

“I’ve never seen that,” said Rob Thompson. “Almost 52 years old and I’ve never.”
Down the road, the damage was even worse.

“The siren went off and Terry said, ‘Go downstairs’ and so we all went downstairs,” recalls Mark Johnson.
The Johnson’s roof was ripped off their pole barn.
“It just got underneath the roof and ripped the whole roof off and sucked all of the insulation out.”

I can tell you right now what happened, and then will show why. This entire roof – steel roofing and wood roof purlins was lifted off from roof truss system because of a poor connection. Long time readers will recall me mentioning how most engineering failures are due to poorly designed or improperly installed connections.

Many Midwest pole building suppliers and contractors provide buildings with sidewall columns anywhere from seven to 10 foot on center. A single pole barn roof truss is placed at each column. 2×4 roof purlins are installed (on edge) across purlin tops. One popular supplier uses a nine foot spacing with 20 foot long purlins to span two ‘bays’ (a bay being space between truss columns).

Design wind speed is 115 mph from 2015 IBC (International Building Code) Figure 1609.3(3). This is based upon IBC Risk Category II for buildings like your home. For this purpose, we will assume an Exposure B for wind site (building in the photo is Exposure C, roughly 20% greater loads). Wind exposure is explained here: https://www.hansenpolebuildings.com/2012/03/wind-exposure-confusion/.

Using appropriate calculations wind load (uplift) for components and cladding in this area of roof is 33.547 psf (pounds per square foot). Weight of roof purlins and steel roofing can be used to resist this uplift (roughly 1.105 psf). This makes our net uplift 32.442 psf.

For the sake of this discussion we will assume purlins are spanning eight feet between truss centers and spaced every two feet. This means each purlin end has 16 square feet of surface to possibly uplift x 32.442 psf or a total of 519.072 pounds.

We are going to attach purlin to top of truss using a 60d pole barn nail (roughly 2/10 inch in diameter). From the 2015 National Design Specifications for Wood Construction (NDS) Table 12.2D with a Specific Gravity of 0.55 (assuming roof truss top chords are Southern Pine – other species may be less) and a nail diameter of 0.200 inches, these nails are good for 109 pounds of resistance per inch of depth of penetration (lbs/in) into truss top chord.

109 lbs/in multiplied by 2-1/2 inches = 272.5 pounds. Because this connection is not controlled by metal strength a load adjustment factor of 1.6 may be applied giving total resistance to uplift of 436 pounds or 19% overstressed.

Even worse would be if a purlin is used to span across two adjacent bays of roof. Using the previous example, our uplift loads at each end would be reduced to 389.304 pounds per end (and working), however at our truss at center uplift would be nearly 1300 pounds!

There does exist some solutions, most economical of width is probably to use engineered joist hangers and place purlins between trusses.

This entry was posted in Pole Barn Design, Constructing a Pole Building, Pole Barn Planning, Pole Barn Structure, Trusses, Fasteners and tagged 2015 International building code, wind exposure B, purlins, wood roof truss, solar panel, poor roof connection on September 5, 2019 by admin.

I am Designing a Pole Barn

I Am Designing a Pole Barn….

These words strike fear in my heart.

Reader ELISEO in FLOWERY BRANCH writes:

“ I’m designing a Pole Barn to be 30’W x 40’L x 12’H. I’m asking for 6 trusses to be placed 8’ on center with a 4:12 pitch. I’m gonna tie them together with 2×4 on edge 24” OC. My question to you is since I’ve been reading through some books and I haven’t had a definite answer. I’ve gotten companies quote a minimum of 11 Trusses and one company actually quoted me 6 trusses like I had originally planned. Do you believe that down here in GA 8’ OC trusses will be up to Code? They will be held on 6x6x12 PT also 8’ OC.”

Elisio’s first challenge is he is attempting to structurally design his own post frame building. Maybe you have seen car commercials on tv, where a vehicle is driven at high speeds on winding roads? Ever notice a disclaimer of, “Driver is a trained professional on a closed course”? It is because you and a vehicle MIGHT be able to perform together just like on tv, however chances are fair you will possibly be injured or even die should you attempt.

This very same adage holds true with those punting at their own building design….engage a trained professional. Or even better, a complete post frame building package structurally designed by a trained professional. And when I talk about “trained professional” in this context, I mean plans sealed by a Registered Design Professional (RDP – architect or engineer) specifically for your building on your property.

Now Elisio’s asking for six trusses to be placed eight foot on center is only partially correct – it would give him a conservative design for his end trusses as they only support four feet from endwall to next truss (plus any end overhang). He might end up having spent more money than necessary. His idea of using 2×4 on edge for roof purlins may or may not work, depending upon grade and species of material. Beyond what type of 2×4 is proposed, will be its ability to withstand wind loads, as wind loads will dictate in Georgia. This, and how to properly connect purlins to trusses, is just a portion of what a RDP will be examining and verifying for adequacy.

Will trusses spaced every eight feet be up to Code in Georgia (or anywhere else)? Read here to find out: https://www.hansenpolebuildings.com/2011/06/pole-barn-truss-spacing/.

Please do not put yourself or your loved ones at risk, call 1(866)200-9657 and speak with a Hansen Pole Buildings Designer who can assist you in having a properly designed post frame (pole barn) building!

This entry was posted in Constructing a Pole Building, Pole Barn Planning, Trusses, Professional Engineer, Pole Barn Questions, Pole Barn Design and tagged trusses, registered design professional, purlins, engineer sealed building plans, Georgia building code, trusses at 8', sealed building plans on May 15, 2019 by admin.

Is an Ice Barrier Required Under Post Frame Roofing?

Like a good novelist, I am going to torture you by forcing you to read this story prior to revealing a super- secret answer.

One of our clients will be constructing a Hansen Pole Building in Colorado soon. This particular building is very typical post frame construction as it has steel roofing over open purlins. There is not a “roof decking” of OSB (Oriented Strand Board) or plywood.

When applying for his permit to build his new building, he was told an “Ice Barrier” would be a requirement.

2015 International Building Code deals with a myriad of roofing products in Chapter 15 (check it out yourself here: https://codes.iccsafe.org/content/IBC2015/chapter-15-roof-assemblies-and-rooftop-structures). These include Section 1507.2 Asphalt shingles, 1507.3 Clay and concrete tile, 1507.4 Metal roof panels, 1507.5 Metal roof shingles, 1507.6 Mineral-surfaced roll roofing, 1507.7 Slate Shingles, etc.

Most of these roofing choices list a requirement such as:

“1507.2.8.2 Ice barrier.

In areas where there has been a history of ice forming along the eaves causing a backup of water, an ice barrier that consists of at least two layers of underlayment cemented together or of a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24 inches inside the exterior wall line of the building.”

IBC 1507.4 Metal Roof Panels does NOT include a subsection for Ice barrier.

Tim Carter of www.askthebuilder.com explains what ice and water barrier is in this video: https://www.youtube.com/watch?v=yVzF5wE3ptc.

Now it is possible for any local permit issuing authority to make amendments to their adopted version of codes. However if my Building Department had such an amendment I would be asking to see it first, then ask how they propose to install it over widely spaced purlins?

This entry was posted in Roofing Materials, Pole Building How To Guides, Pole Barn Planning, Steel Roofing & Siding, Insulation, Pole Barn Questions, Pole Barn Design, Building Department and tagged International Building Code, purlins, Tim Carter, Metal Roof panels, Ask the Builder.com on March 19, 2019 by admin.

Where Oh Where Should My Purlins Go?

Where, Oh Where, Should My Purlins Go?

There are almost as many methods for assembly of a post frame building, as there are post frame buildings! I kid you not.

Reader KELLY writes:

I like the hanger between trusses, for roof load, but I wonder if you give up some of the diaphragm strength that is accomplished by purlins laying flat on the truss.

Trusses most likely on 8’s. Purlins 24 spacing.”

Mike the Pole Barn Guru writes:

This leaves “in hangers” between trusses as your only viable (and practical) design solution.

This entry was posted in Trusses, Pole Barn Questions, Pole Barn Design, Pole Barn Planning, Pole Barn Structure and tagged building plans, registered design professional, purlins, 60d nails, pole building diaphragm, trusses, pole building plans on February 20, 2019 by admin.

What Kind of Trusses Are Pictured?

This question was posed by Hansen Pole Buildings’ Designer Doug. Photo isn’t of a Hansen Pole Building, probably raising questions in Doug’s mind as it looks rather foreign.

Solid blocking should be placed between end overhanging purlins to provide continuity of a load path from roof diaphragm to ground. As being built, load path has been divided.

Perimeter beams in this photo show to be inset between the columns. My curiosity wonders how they adequately attach? Your guess is as good as mine.

This entry was posted in Pole Barn Questions, Pole Barn Design, Building Overhangs, Pole Barn Structure, Trusses and tagged purlins, single trusses, lean-to, paddle blocks, outriggers, double trusses on January 10, 2019 by admin.

Installing Joist Hangers

Installing Joist Hangers on Opposite Sides of a Double Truss

My friend and loyal reader LONNIE in COLORADO SPRINGS is one Hansen Pole Buildings’ client who truly puts thought into the assembly of his new post frame building.

Lonnie writes:

“I’ve been pondering and pondering this and I may have a solution that I want to run by you. I’m considering buying a Bostitch F21PL framing nailer to use on the project and mainly because it includes a metal connector tip that will allow it to drive the 3” nails through the hangers for the purlins. What I was thinking of doing is to frame each truss bay using 2@ 1 1/2” 10d nails (always making sure to use the same 2 holes for each hanger… i.e. upper left and lower right) to build each bay on the ground. After raising the truss bays, go back and attach the double trusses together and at the same time finish the hangers with two 3” 10d nails in the empty hanger holes. The only concern I had was that the 3” nails would be driven opposing the 1.5” nails on the opposite truss hanger. However, since the nails would be driven point to point I think the odds of the 3” driving the opposing 1.5” out would be very slim.

Do you think that mix of 1.5” and 3” nails for the connectors would be sufficient or should I really consider just temporarily attach the hangers and replace the temporary attachment with the 3” nails? If that is the case, is there an issue driving 3” nails basically tip to tip through the hangers?

Mike the Pole Barn Guru writes:

Your mix of nails will be more than adequate, as the load carrying capacity of the hanger is greater than the ability of the roof purlin to carry a load. In simple terms – the hanger and its fasteners are not the weak link in the system. Also – if you take two hangers and place them back to back, you will notice the holes do not all line up – whether the variability is accidental or purposeful, I do not know, however it further reduces the probability of nails from opposite directions exactly hitting each other tip-to-tip.

A caution – situations involving a differentiation from what is shown on the actual engineer sealed plans should always be verified for structural adequacy prior to implementation.

This entry was posted in Fasteners, Pole Barn Questions, Pole Barn Design, Constructing a Pole Building, Pole Barn Planning, Pole Barn Structure, Trusses and tagged purlins, 10d nails, Bostitch, framing nailer, double trusses on June 29, 2018 by admin.

Extreme Efforts to Add Post Frame to House

Extreme Efforts to Match Post Frame to House

Reader JOSH from POST FALLS and I have previously communicated. He is doing what I refer to a piecemealing – putting together his own building by making repeated trips to the local lumber yard (learn more about piecemealing here: https://www.hansenpolebuildings.com/2014/03/diy-pole-building/.

Josh’s new post frame garage is adjacent to his home and he wants things to match up.

Josh writes:

“Thanks so much for your offer for help. The knowledge of other people’s questions on your site is a great resource. I’ll buy my next pole structure kit from you for sure.

Quick question. I have an 18″ overhang with 2×8 purlins and truss top members. My pole garage is next to my house and will be matching the exterior of the house. The varge rafter and fascia on the house are 2×6. It looks like I can just trim the bottom off on the fascia side, but what is the recommended way to match the gable end to the house if the purlins on the garage are 2×8 instead of 2×6?

Also are the varge rafter and the facscia both 1×6? or 2×6?

P.S. I noticed you used grok in one of your answers to a question. Haha, first use of grok in a non-technical setting I’ve seen. You must have a technical background.”

Mike the Pole Barn Guru Writes:

My mission is to be informative and entertaining – if grok got a chuckle from you, then all is good! I also try to throw out some occasional words most people do not use every day, with the hopes it will expand the vocabulary of some.

Unless your pole garage is attached to your house, frankly no one except you or I would ever notice the fascias are not the same dimension. People just are not finely attuned to details such as these. If it is really important to you, you could cut the overhanging portion of the purlins down to 5-1/2″ by ripping a chunk off from the overhanging portion, without it negatively affecting the structural ability of the purlins to carry the load. Your Building Department may require a letter from the engineer who designed your building on this one, however.

I would go with two inch nominal material for both the varges and fascias – they will be far straighter and will tend not to wave as much between supports.

This entry was posted in Pole Barn Questions, Constructing a Pole Building, Trusses, Pole Barn Homes and tagged purlins, pole barn house, post frame garage, fascia on October 13, 2017 by admin.

Roofing Before Siding

If I am not mistaken, somewhere in the not too distant past I have expounded upon how I know a particular builder is or was a stick frame builder. How can I tell? The giveaway is they feel compelled to build the walls before the roof. I’ve listened to many experienced post frame builders in my career, as well as having constructed a few (hundred)post frame buildings myself.
The verdict – for best results, frame the roof and install the roofing prior to any wall framing being done.

Why?

First point is, if by some odd chance the columns at the base of the building are not exactly where they ought to be, the roof can easily be squared up still. It is relatively easy to move the tops of columns which are not framed to or sided. This allows for the column tops to be placed where they should have been at grade level.

Secondly, all of the roof purlins in interior bays can be precut to exactly the same length (in most cases), or at the very least an entire bay can be done at a time. If the column spacing varied between sidewalls and columns tops were not where they should have been, it would take custom cutting to length every roof purlin all of the way across the building. Neither fun, nor time efficient.

Third, without siding installed, it is relatively easy to square up each roof plane to make installing the roofing as painless as possible. Once either the steel roofing or roof sheathing with shingles is installed, the roof planes will be affixed where they should be.

Fourth, much easier to drive a pre-mix concrete truck around the perimeter of the building and chute the concrete in for a slab on grade floor. No framing or siding to get in the way, only widely spaced columns.

Am sure there are more reasons than just these, however the factors stated should be enough to convince any builder (or DIYer) to give it a try and see if in the end, the result isn’t far happier

This entry was posted in Pole Barn Questions, Roofing Materials, Steel Roofing & Siding and tagged purlins, columns, roofing before wall framing on October 12, 2017 by admin.

Rehashing Eave Height

Eave height on post frame buildings seems to be a challenge for some folks. At Hansen Pole Buildings, we do make some efforts to see to it our clients (or more often the builders some of them hire), actually build to the correct height.

How important is it to get this correct? After having a solid foundation, this would probably be number two on the list.

My long term readers are going to begin having drool run out the corners of their mouths quickly, as I have harped (oops – expounded) upon the subject frequently in the past.
Today’s lesson is due to one of our clients who is currently erecting his pole barn. This particular building has overhangs on the gabled endwalls, fashioned by lowering the end truss by the thickness of the roof purlins. This allows for the purlins to run over the top of the purlins to support the overhang. It makes for one sturdy overhang which isn’t going to sag.

The question?

“Where it says lower end truss by 7 inches and 5/8 of an inch? Can you please confirm this? Doesn’t this mean the eave will be lower than 12 feet?”

Mike the Pole Barn Guru Responds:

Our client was spot on with how far to lower the trusses on the end of his building.
Today’s answer on eave height lies with some extended light reading, enjoy: https://www.hansenpolebuildings.com/2015/02/eave-height-2/

This entry was posted in Pole Barn Questions, Building Overhangs, Constructing a Pole Building, Trusses and tagged purlins, overhang, correct eave height on October 5, 2017 by admin.

Save Me, My Trusses Do Not Fit!

Here is a case where investing in a post frame building kit from people who have actually constructed buildings is a huge asset (am surmising this is not the case, since this person sent the Hansen Pole Buildings Technical Support email address a plea for help).
Reader James writes: “I have a 24 x 60 pole barn. I pulled my outside dimensions from outside of skirt board now on my trusses are an inch and a half long on each side how can I fix this?”

Dear James ~

Since I do not know who supplied your post frame building kit package, I will have to do some guessing as to how your post frame building was designed. Typically questions like this can be answered by whomever provided your plans and materials – and if it is an engineered building, the building engineer should be consulted as well.

A quick solve for anywhere in the country and any method of construction – to the eave outside of all corner and sidewall columns, attach a pressure preservative treated 2×6 from grade, up to the level of the trusses. In most cases two 10d galvanized common nails spaced every nine inches will be an adequate connection. As these 2×6 will be in contact with the ground, they should probably be treated to at least a UC-4B standard. Your building’s skirt board and any other exterior mounted framing can now be attached to the face of these 2×6. Using this method allows for siding to be installed normally, without any undue compensations to get it to lay out properly.

Another possibility – provided the heel plates of the prefabricated light gauge metal connector plated trusses are not in the way, you could cut 1-1/2″ off of the end of each truss, making them 29’9″ to match the width of your building from outside of column, to outside of column. In no case cut through a steel truss plate.

Or, (in cases with recessed or joist hung purlins) attach the eave girts between the overhanging 1-1/2″ of each truss. The end connections end up being a bit trickier here as it requires nailing through the end of the truss, into the end grain of the eave girt.

With stacked purlins, the eave girt can be nailed to the outside face of the columns above the truss.

If the chosen path is any of the last three choices, when the endwall steel is placed, start the first panel of steel 3/4 inch PAST the corner of the building. The corner trim will cover this and it eliminates having to do a lengthwise rip on the last sheet of steel on the opposite corner.

Mike the Pole Barn Guru

This entry was posted in Pole Barn Questions, Building Overhangs, Trusses and tagged purlins, Mike the Pole Barn Guru, stacked purlins, steel truss plate, post frame building on July 28, 2017 by admin.

Purlin Questions for the Engineering Department: Building Disaster Part IV

Purlin Questions for the Engineering Department

For those readers just joining us, go back to Tuesday through Friday’s blogs to catch up to the following story…

Our client (after discussing possible corrections with one or more builders) poses this:

“I have two questions I’d like to ask of the engineering dept.

1.) Is there an acceptable way to inset the grade boards to be flush with the posts? Perhaps with hangers? If so, it would mean the wall girts would not have to be furred out.

2.) Would building frames for the end wall overhangs, and attaching them to the end trussses a viable option? Or do they feel like the end trusses would need to be lowered so the purlins can be extended?

I don’t know all of the terminology. Hopefully the above makes sense.

Thank you.”

Any proposed “solution” at this point is only a suggestion for discussion. A revised set of drawings should be produced and sealed by the engineer of record to incorporate the ultimately agreed upon repair fix.

Answers…

(1) Place a UC4B Pressure Treated 4×4 block at least 7-1/4″ long on each side of the column at the level where the 2×8 skirt board would attach. Use 3- 5″ Ledgerlocks to attach block to column. Pre-drill for them and stagger to avoid splitting. Drive 6-10d common nails through skirt board into 4×4 block. Cut ends of 4×4 block and 2×8 skirt board to be painted liberally with Copper Napthenate. Place (2) Simpson Strong-Tie LSTA12 straps across each column to tie from one skirt board to the next. Any 10d nails driven through the LSTA12 into the 2×8 PT and block would count towards the total of six.

(2) Building a “ladder” floating in space is far from an ideal solution. If they opt for this, I would want to see an LSTA24 on top of each purlin split 50/50 between blocking in the ladder and the purlin behind the truss, with 10d nails in each hole. Ladder would need to be built of 2×6 and also nailed through the 2×6 on the building side of the ladder, into the top chord of the end truss with 2-10d @ 12″ o.c.

Ultimately repairs can be simple, difficult, low cost or spendy. In the end the least expensive solution for question number one will be to furr out the girts by nailing a 2×4 flat across the columns at each wall girt. Fairly easy to accomplish and not overly expensive in time or materials.

The right way to do number two is to remove all of the purlins from the end bay, take down the end truss, cut the notches into the columns to support it (as detailed in the plans) at the correct height, and properly place the truss. This will entail the purchase of longer purlins, however it will give a much better end result.

And this my friends, is the end to my story about a building “gone wrong”.

This entry was posted in Trusses, Pole Barn Questions, Pole Barn Design, Building Overhangs, Constructing a Pole Building, Building Contractor and tagged purlins, skirt board, overhangs, furring out wall girts, LSTA 12 on June 30, 2017 by admin.

There ARE some truly excellent builders: Hansen Building Disaster Part II

There ARE some truly excellent builders…

This just isn’t one of them.

In our last episode, the ‘builder’ had botched the shearwalls. A minor issue compared to what comes next.

This building was designed to have enclosed overhangs on all four sides. On the endwalls the roof purlins project over the top of the end truss to support the overhang.

I said, “the purlins project over the top of the end truss to support the overhang”.

Obviously this escaped said “builder” as he cut off all of the purlins and fit them nicely behind the end truss.

The end truss was to have been lowered so the purlins could go over the top of it. The distance to lower the end truss is only spelled out twice on the plans, so it could easily have been missed. Well, maybe not easily. There is also a detail on page four of the engineered plans at 1-1/2” per foot which shows exactly this circumstance.

If this wasn’t enough, an entire chapter for the Hansen Pole Buildings’ Construction Manual is devoted to this overhang sequence!

But wait – there is more.

And it gets even (if this is possible) worse!

See the pretty truss on the end of the building? Not only is it 5-13/16” too high, it is designed to be placed into notches cut into each of the end and corner columns.

The lack of adequate bearing on these columns is a huge structural challenge, as under a load there is little to keep the truss from wanting to slide down the face of the column except nails.

When end trusses are properly notched in, there is 2×4 siding backing placed flat on the face of the bottom and top chords of the truss. A horizontal 2×4 is to be placed at mid height of the truss to attach the siding to, so it is not over spanning the capabilities of the siding.

The siding backing on the bottom chord of the truss also serves as bracing to create a three inch thick member, reducing the chances of the end truss bottom chord buckling under extreme loading conditions.

Stay tuned to this channel – the fun is not over yet!

This entry was posted in Building Contractor, Pole Barn Design, Building Overhangs, Constructing a Pole Building, Pole Barn Structure and tagged purlins, engineered plans, end overhang, Hansen Buildings Construction Manual, siding backing on June 28, 2017 by admin.

Post Frame Building Clients Can Be So Fun

Post Frame Building Clients Can Be So Fun!

In providing “The Ultimate Post Frame Building Experience”™ Hansen Pole Buildings is not selling buildings to anyone – we are providing a service. If there is such a thing as a past life or lives, I must have been some sort of instructor in a past life. I am so enjoying our clients who want to know about their buildings, how they work and how to get the ultimate strength results from the new post frame building kit packages. These are the clients whom I know will easily construct a finished building with far better workmanship than they could ever pay a builder to do.

One of my current favorites is a Mr. W. I have never had the privilege of meeting him in person, we have not even spoken on the phone. However we’ve had some super email interactions. I could be mistaken, but he seems like the type of person with whom I could sit for hours and discuss buildings over cold adult beverages.

I’d like to share with you a recent exchange between us:
Ralph wrote:

“Thanks for the excellent information! Very encouraging to have these pesky issues put to bed.
I have Joist Hanger questions on the LU28’s that hold the 2×8 Purlins:

1. I assume I will nail perpendicular through the holes? Not angled like the LUS style hangers?
2. 8 nails into the truss? Use all the holes?
a. Double truss should I use 10d x 3” common HDG? Or just use 10d x 1-1/2” joist nails always?
b. Won’t nails into hanger on opposite side hit these nails or cause problems if using 10d x 3”?
c. Single truss should I use 10d x 1-1/2” joist nails?
3. 6 nails into the purlin? Use all the holes?
Use 10d x 1-1/2” joist nails?
4. All the purlins are under compression except at the single truss ends. Should I use SDS screws on the hanger-to-truss ends? The sheet metal will eventually provide the compression needed I’m sure.

Thanks,
Ralph”

To which I replied:
“Mr. W. ~

Thank you for your kind words.

When using engineered hangers, always nail in the direction of the holes (if no “bubble”, so the hangar nailing area is flat, nail straight in). Always nail through every hole which will allow for the fastener to have tips into wood without causing undue splitting. In most instances, only a portion of the holes actually need nails to be adequate to support the appropriate loading conditions, however having open nail holes tends to become problematic to field inspectors and we prefer safety over remorse.

In double trusses use three inch nails, if you place two hangers back to back, you will notice the holes in the flanges do not align with each other for this very reason. Single trusses – use 10d x 1-1/2″ nails. While the nails will prove to be adequate, SD screws (in my humble opinion) are a superior fastener and I encourage their use whenever possible and practical.”

Kindest Regards,

Mike the Pole Barn Guru

For related reading:
Simpson Strong-Tie® hangers:

https://www.hansenpolebuildings.com/2013/08/simpson/

and

https://www.hansenpolebuildings.com/2016/02/hang-those-joist-hangers/

Strong-Drive® Screws (aka SD screws):

https://www.hansenpolebuildings.com/2017/03/simpson-drive-screws/

Joist Hanger nails:

https://www.hansenpolebuildings.com/2013/01/tico-10d-common-nails/

This entry was posted in Fasteners, Pole Barn Questions, Pole Barn Design, Constructing a Pole Building, Trusses and tagged purlins, joist hangers, the ultimate post frame building experience, LU28 hanger, joist nails, SDS screws on June 16, 2017 by admin.

A Serious Case of Roof Steel Leaks

This is one of those “Dear Pole Barn Guru” letters which I feel bad for the client in having to answer. The client has paid good money to have his new post frame building constructed, only to have installer challenges render the end result as far less than ideal.

For your reading pleasure:

DEAR POLE BARN GURU: The Hansen pole barn kit I bought has 26 gauge steel roofing put on twice by a licensed contractor that still leaks profusely. A licensed roofer suggested 50 year shingles. Will the trusses bear the weight of a wooden deck and shingles? What’s the expected life span/warranty on your 26 gauge steel roofing from ABC in SLC? TOM in SHERIDAN

DEAR TOM: I’ve had seen the photos of your roof from the inside, as near as I can tell, the roof purlins were not originally set in a straight line from one end of the building, to the other. It then appears the roof steel was predrilled, causing a plethora of screws to miss the purlins as installation progressed from the end towards the middle. The only real solutions are to add lots of framing under all of the holes (so every screw goes straight into the underlying framing) or to remove the roofing, align the purlins and then install new steel over them. If the roof plane is square, the purlins are placed in straight rows and the roof steel is predrilled to properly match the purlin spacing, there is no reason it should leak – other than plain installer error. Placing screws through holes at an angle, or using caulking is not an adequate repair.

As with most post frame (pole) buildings, the roof has been designed to support the weight of the trusses, roof purlins, minimal roof insulation (to prevent condensation) and the roof steel. In order to support OSB or plywood and shingles, at a minimum the roof would need to have been designed for a 7 psf (pounds per square foot) dead load, rather than 3.3 psf. It might be possible to get an engineered repair to the trusses to increase the load carrying capacity, but it is unlikely it would be an easy, or inexpensive, fix.

The steel warranty information is available on our website at:

https://www.hansenpolebuildings.com/pole-building-faqs/product-warranties/

In your climate, properly installed, your steel roof should last longer than either you or I.

On a side note – a “50 year” shingle typically has a very rapid decline in what percentage of replacement material (no labor) is covered. Here is the true story of shingle warranties:

https://www.hansenpolebuildings.com/2015/03/shingle-warranties/

This entry was posted in Building Contractor, Pole Barn Questions, Roofing Materials, Steel Roofing & Siding and tagged purlins, roof steel leaks, repairing roof leaks, 50 year shingles, steel warranty on January 26, 2017 by admin.

Termites and Pole Barns

A Buggy Situation

A client writes to Justine (the Hansen Pole Buildings’ Order Fulfillment goddess) this week:

“I was hoping to get some advice. I’m still working on the building having just completed rafter placement and was starting to pull apart the two bundles of lumber for the purlins. When I started pulling boards out of the bundle I noticed some surface damage that just kept getting worse as I sent through the stack of lumber. Toward the center there was a large amount of termites, see pictures. The odd thing was it only affected the stack of 2X6X10′ boards, the other bundle of lumber, sitting right next to it was untouched. This is really unusual for our area where summers are hot 90-100° with very low humidity <15-20% making termites a very rare issue. The lumber was stored as instructed in your manual but now we have a probably 1/2 of the 2X6X10′ boards that are damaged significantly. Since termites are not a large problem in this area and all of the infestation was in the center of a stack of very wet wood (not from any rain or external water) and there was no damage to the stack sitting next to it, I suspect it came with termites but of course I can’t prove that so as disappointed as I am let me get on to the request for advice. These boards are primarily used for the purlins and horizontal siding support around the outside of the building. I know the purlins are structural and need to be 100% clean wood, but is some level of damage acceptable for the horizontal boards between the posts? If so, how much, or is any penetration by the termites into the wood render it unusable? “

Personally, I feel bad for the client, however he did take delivery of the materials back in April and on May 3 he wrote to Justine:

“I have all of the material and all is in good shape. Thank you for all of your support”

On one hand client has received everything in good order, on the other hand nearly four months later there are some challenges. It is possible the lumber was shipped buggy – wildly random things do happen. It is also possible the material got wet in the spring and the heat from the 90-100 degree summer days caused the relative humidity in the center of the unit to increase as the unit was likely paper wrapped. In either case, it ended up as the perfect breeding ground for pesky little critters.

The lumber grading rules are fairly generous about allowable defects, so some of the damaged materials may be able to be used.

Here was Justine’s response (spot on by the way):

“We would happy to provide some advice for this situation. Let me first say this is why we stress so much to inspect and inventory wood as they arrive up front. You are probably correct in your conclusion they came with the mites in the bundle. If the bundle would have been opened then we could have probably avoided your current situation.

To answer your question, yes there are some level of acceptable defects in lumber. Keep in mind the wall girts are just as crucial as the roof purlins in supporting the loads of your building.

You can read about these allowable lumber defects on our blog: https://www.hansenpolebuildings.com/2013/12/lumber-defects/

I would generally apply some common sense on how I use certain boards and which ones I decide not to use. I would say first take the boards you deem usable but in the worst shape in locations which don’t provide as much structural value like in blocking locations. For girts and purlins they don’t need to be perfect but anything meeting the allowable defect rules it will work for those locations but I would try to keep the better boards for those two locations. Anything which does not meet the minimum requirements will have to be replaced.”

Moral of the story – regardless of whom you buy your building from, or where the lumber came from, inspect it thoroughly at time of delivery for defects as well as surprises. This allows for anything out of the ordinary to be taken care of promptly, before feelings get hurt. And, always try to use materials as expediently as possible, the sooner they become part of your new post frame building, the happier they will be.

This entry was posted in Lumber, Pole Barn Questions, Pole Barn Design and tagged purlins, lumber grading rules, lumber allowable defects on August 31, 2016 by admin.

What does 2×6 Lumber Weigh?

Is 2×6 lumber heavy?

This is actually fairly important, not just to determine how many boards can be toted around a jobsite by one person, but also in calculating the dead loads which must be carried by structural members such as roof trusses and rafters.

Like most things played around with by engineers, and other people with too much time on their hands, there is a formula to calculate this (please feel free to scream in anguish now):

62.4 X [ G / (1 + G X 0.009) X (m.c.)] X [1 + m.c./100]

Whoo Hoo!! If this isn’t fun…..like watching paint dry?!

Seriously, it is not so tough. G is the value of the Specific Gravity of a known species of lumber. In the U.S. the most popular choices for framing lumber are Southern Pine (G=0.55), Douglas Fir-Larch (G=0.50), Hem-Fir (G=0.43) and Spruce-Pine-Fir (G=0.42).

The moisture content of the lumber is expressed as the “m.c.” above. Lumber stamped as “dry” has a maximum moisture content of 19%.

Picking Dry Hem-Fir and filling the appropriate blanks into the formula gives, 62.4 * [.43 / (1 + .43 * 0.009 * .19)] * [ 1 + (.19/100)] = 26.86 pcf (pounds per cubic foot). So a 12 inch cube of dry Hem-Fir should weigh 26.86 pounds.

A cubic foot has 1728 cubic inches (ci). 2×6 has finished dimensions of 1-1/2 inches by 5-1/2”, or 99 ci in lineal a foot. Taking the weight calculated above (26.86 pcf) dividing by 1728 and multiplying by 99, gives the weight of a foot of Hem-Fir 2×6 as 1.539 pounds (lbs).

Want to pack around 12 foot long 2×6 lumber? In Hem-Fir, it will weigh 18.466 lbs.

Think of dead loads as the weights of materials which are permanent. In the case of a typical pole barn roof, purlins will always be there supporting the roof sheathing.

If purlins are placed two foot on center, up the slope (or run) of the roof, the dead load attributed to the purlins can be determined by dividing the weight per lineal foot (1.539 lbs calculated above) by the spacing of the purlin (in feet) divided by the cosine of the roof slope. In this case, it is roughly 0.81 psf (pounds per square foot).

Not a lot of weight, but it still must be accounted for. As well, 60% of dead load weight can also be used to counteract the forces of uplift.

So much for the math lesson of the day.

Now, aren’t you glad you asked?

This entry was posted in Lumber and tagged dead loads, lumber weight, purlins on February 8, 2013 by admin.

Purlins: Missing Screws

Just in case I have never mentioned how much I appreciate the questions posed to me by Bob, one of the Hansen Pole Buildings’ Designers, I will do so here.

Bob writes,

“I got into a discussion with a gentleman in Kansas that liked our design approach (post spacing, double interior trusses, purlins on edge, etc.) but has no faith at all that he or his crew would hit all of the purlins on edge with the roofing screws. We discussed pre-drilling and I had him off the ledge, but when the discussion of book shelf girts came up, he started breathing hard again. Now I’m pretty sure book shelf girts is the only option these days for any pole barn, but it seems I’m dealing with a client that is afraid of pre-drilling and his ability to square his roof and building.

One of your blogs describes the simple fix for a missed hole (“Either push the underlying purlin up towards the peak of the roof, or push it down towards the eave line until the pre-drilled hole aligns with the center of the purlin.”) but I’m having trouble imagining being able to push a purlin that is in place that far. And if a purlin is pushed into position as described, what happens upon release? Maybe this is a situation that I could appreciate more with personal experience, but I’m not getting there with my imagination alone… and as a result I won’t be terribly convincing that it’s really that easy.”

The beauty of pre-drilling pilot holes for roof and wall screws is perfectly straight lines. Straight screw lines are truly a thing of beauty – there are few things in life as pleasing as looking across a wall or roof and seeing the screws lined up like soldiers.

In an ideal world, every piece of lumber would be absolutely perfectly straight, and remain this way forever. Lumber, even though it is produced in a factory (a sawmill), is organic – it really wants to return to its nature as a tree. This means it wants to warp, twist, cup, crook or otherwise deflect.

The wonderful thing about lumber is it will flex a long way in the weak (1-1/2” narrow direction). This is exactly why wall girts placed flat on the outside of columns rarely meet the requirements of the codes – they deflect too far!

With both ends of a roof purlin restrained by an engineered joist hanger, or wall girts restrained at each end by solid blocking, the only portion of the framing which will be a potential for a “shiner” is as the girt or purlin approaches the middle of the span.

In the Hansen Buildings product guide (downloadable free on our website), is a photo of my feet (seriously) – as I stand on a 2×6 laid flat (I am standing on the wide 5-1/2 inch face. The 12 foot long 2×6 probably bends close to six inches at the center!

Whilst Bob (and his client) may be concerned about the ability to move purlins or girts up or down, the reality is – wood is forgiving, it can be moved remarkably easily to where it should have been had we been living in the previously mentioned ideal world.

And remember, steel roofing and siding functions much like very strong, very thin plywood. Once the screws are in place, the strength of the screws and the rigidity of the steel will easily hold everything where it ought to be.

FOOTNOTE: (Added by JAHansen, Mike’s wife) – Coming into the pole building business over a dozen years ago, knowing absolutely nothing about lumber, steel and the like, I can certainly identify with the skeptical client. When you haven’t experienced the ease of building with lumber, 1-1/2” sounds pretty small to “hit” with a screw!

However, I can testify as a true novice at building, Mike’s words are straight as an arrow. I’ve personally assisted on half a dozen buildings over the past years, and I can say almost every time there was a purlin or girt that looked like the screws were going to “miss” – especially on the wall girts where the weight of the wood sometimes caused the center to droop down an inch or more. The holes near the ends were not a question for putting the screws into the wood. Because they are near the ends, the holes were “right on”. We made sure on the center of each purlin or girt to use a block of wood as a support (wall girts) or in case of the roof purlins a “lever” to push the center into alignment. It’s much easier than it sounds, and yes, the screws were dead on.

Thousands of pole buildings have been built, with no leaking roofs. That should be solid proof, but if you still have doubts – go watch a pole building being constructed. Seeing is believing.

This entry was posted in Pole Barn Structure, Steel Roofing & Siding, Powder Coated Screws and tagged girts, purlins, roofing screws on August 22, 2012 by admin.

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