Tag Archives: OSB

Pier Insulation, Hold Up Distances, and Site Prep

This week the Pole Barn Guru answers reader questions about insulating around outside of post piers, the hold-up distance of any non-treated lumber or wall sheathing, and if laying gravel prior to drilling and setting columns would be best order of building.

DEAR POLE BARN GURU: Kind of a 2 parter. I am trenching 4′ straight down around the perimeter (in between posts, just inside the splash plank) of my post frame home. Should I also do the porch on the front of the house? Also I was told I should insulate around the outside of the post piers as well to prevent frost heave. Is this necessary? If so how would I do that if my collard are already poured? DYLAN in GLENWOOD

DEAR DYLAN: Your easiest design solution is to place rigid insulation boards down 2′, then out horizontally (most Building Departments accept 2′ out). This places all of your insulation above tops of concrete collars. This guide should prove helpful (keep in mind, it is for traditional stick built, but concrete has no magical frost preventive properties, so replace “concrete” with compactable fill): https://www.huduser.gov/publications/pdf/fpsfguide.pdf Your porch is best insulated, not only around perimeter, but also under slab itself.

 

DEAR POLE BARN GURU: Hey I see you post a lot on the pole building pages. I have a question about vinyl siding on a pole building and how to keep the OSB water proof. Which a traditional pole building you have your metal siding attaching to your skirt board, but with vinyl siding you have OSB nailed to your skirt board and then tyvek then your siding. How do you keep the OSB board from wicking water up from the ground when you back fill on the outside of the building? Is there a proper way to keep that water tight? STEVEN in CENTREVILLE

DEAR STEVEN: By Code – any non-treated lumber or sheathing must be kept at least six inches above grade. When we have OSB or plywood sheathing, or T1-11 siding, we use a 2×10 pressure treated splash plank, so there is still 3-1/4″ of splash plank to nail to when sheathing is held up 6″.

 

DEAR POLE BARN GURU: Is it ok to put in the gravel leveled and compacted before the builder starts building the post type garage This is what they like, not sure why. Thanks. DAVID in SHEPHERDSVILLE

DEAR DAVID: It is going to be far easier (and less expensive) to properly grade your site and compact fill before your building begins, than trying to do it afterwards. Working equipment around posts and walls is going to be time consuming and can result in structural damage, if not done carefully.

Exactly Identical and 20% Less

Exactly Identical and 20% Less

There is always someone willing to sacrifice quality and/or service to get to a lower price. I have seen it over and over again for decades now.

Price shoppers, or deal hunters, seem to be most interested in the lowest price. Unlike value shoppers who are willing to pay more in favor of an increased sense of value, deal hunters will only pay less and are willing to accept less.

I had an interaction recently with a potential client from rural North Dakota, who is looking to invest in a new post-frame building for a garage/shop. He had received a quote for a similar dimension building from a large vendor who advertises they will save customers big money and their price was quite a bit lower.

In my humble opinion, this client really wanted to do business with us – he was a value shopper, not a price shopper. He did offer to share his quote with me and I found it to be interesting, as it was a multi-page list of materials, rather than stating possibly important things such as building dimensions, design loads, etc.

My goal has always been to assist clients to help them avoid making choices they will regret forever.

Below is my response to this client:

Thank you for your patience while I have gone through xxxx quote. Here are some things I noticed:

xxxx building is not engineered and there is no stated design wind speed or exposure, both of which are critical for adequate structural design.

xxxx is furnishing nailed up columns, with 22′ ones being spliced. I did destructive testing of steel plate reinforced nail-lam columns at Oregon State University. Didn’t work out as well as I had hoped – as the center member takes twice as much load as outer plies (due to nails from both sides going into center member) and failed every time.

They do not furnish posts for either side of entry doors

Their quote included OSB under roof steel, however screws do not hold in OSB and a 1″ screw would penetrate only 1/2″ into blocking between trusses, if added.

Their quote did not include wall OSB or housewrap.

Entry doors – builder grade, primed only, in wood jambs, as opposed to insulated commercial steel, in steel jambs, factory finish painted.

We used to buy overhead doors from Clopay (parent company of Ideal). Ideal doors typically have very low cycle springs and use nylon hinges as opposed to steel.

Our buildings utilize double trusses aligned with interior sidewall columns, to avoid the possibility of a single truss failing and pulling the balance of the roof down with it.

Ventilation should be intake at eaves, exhaust at ridge for best airflow. Endwall soffits should be non-vented and there should be no gable vents.

There is no Z trim on xxxx quote between wainscot and steel panels above.

Delivery not included from xxxx.

Attached quote is how I would want my own building…..

Commercial wall girts for insulation (2×8 on eave sidewalls), framing is included to be drywall ready. https://www.hansenpolebuildings.com/2019/09/11-reasons-post-frame-commercial-girted-walls-are-best-for-drywall/

Trusses with raised heels, so ceiling insulation will be full depth from wall-to-wall https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/

Raised panel (not industrial looking ones xxxx quoted) insulated WIND-RATED overhead doors https://www.hansenpolebuildings.com/2014/12/wind-load-rated-garage-doors/

Roof steel with an Integral Condensation Control https://www.hansenpolebuildings.com/2020/09/integral-condensation-control-2/

Besides fully engineered plans, showing location and connection of every component, you get our 500+ page step-by-step construction manual and unlimited free technical support from people who have actually built post frame buildings.

Will this potential client actually order his new building from Hansen Pole Buildings? There is a distinct possibility and if his choice is to invest elsewhere, at least he has hopefully gained enough insight to make an informed decision.

Permit Problem, OSB Wall Sheathing, and a Flat Roof Slope

This week the Pole Barn Guru answers reader questions about a permit problem for building the reader would now need a permit for, whether or not OSB wall sheathing is necessary for an addition, and if a 12′ peak to 10′ eave will appear flat.

DEAR POLE BARN GURU: I built a pole barn in 2020 without a permit. I sank the posts (6″ x 6″ red fir) in the ground 4′. However, I did not use concrete under the poles or around the poles. Since the ground is quite rocky here I just sunk the poles in the ground. Prior to inserting the poles in the ground I burned the poles with a torch and then painted 3 coats of asphalt paint on them for treatment.
I am now wanting the building to be a commercial building and need to go through the permit process with my county. I don’t think how I built it is to code and wondering if you have any ideas on how to make it right after the fact? Build a foundation under slab and tie the poles to it?
Any recommendations are welcome. Attached are my drawings. MICHAEL in EL RITO

Building PermitDEAR MICHAEL: As you have realized, your immediate challenge is your columns, their lack of adequate treatment for structural in ground use, and a missing foundation system.

Your solution is going to involve hiring a Registered Professional Engineer, experienced in post frame construction and registered in New Mexico, to review your ‘as built’ situation and approve appropriate fixes throughout your structure. I am copying him with this response and will forward your drawings to him as well.

Most likely solution will be for your untreated building columns to be cut off an inch above any existing (or future) concrete slab. Concrete piers can be poured beneath each column (once remaining embedded column has been removed) adequate in dimensions to prevent uplift, overturning and settlement. Code Approved wet set brackets can then be placed in each pier and bolted to column.

 

DEAR POLE BARN GURU: Have a 32’wide by 30’long pole barn garage heated and insulated going to add on for storage only. It will have a concrete floor with vapor barrier and 2 inches of rigid foam. The walls and ceiling will be steel. There will be a 1 foot overhang all the way around to match the existing building, and one garage door at the rear of the building. The eves will be vented along with a rig vent. My question is that normal I would have used OSB for roof and sidewalls cost is an issue, what are your suggestions for the underside of the steel in both the walls and roof? ERIC in IRONS

DEAR ERIC: Provided your addition is properly engineered, there should be no structural reason to sheath your walls or roof with OSB or plywood. Order your roof steel with an Integral Condensation Control factory applied and between wall framing and siding place a Weather Resistant Barrier (Tyvek or similar).

 

DEAR POLE BARN GURU: I am wanting to build a single slope pole barn. The highest point would be 12 feet and the lowest 10 feet. Is that enough height difference to create a slope or will the roof appear to be flat? ZOE in LAREDO

DEAR ZOE: It will depend upon how wide your building will be. If 12 feet wide, it may appear okay, if wider, it is going to start to look flat. One thing to keep in mind, most steel paint warranties are void on roof slopes of less than 3/12. Side lap sealants are also required for steel roofing on slopes under 3/12, adding to investment and complexity.

Insulating an Existing Pole Barn

Insulating an Existing Pole Barn When Things Started Wrong

Reader TOM writes:

“Mike,  I have an existing pole barn (6×6 post with 2’ on center girts ) that has a 4” concrete floor with 10 mil plastic under it. The side walls have 1” XPS insulation on the outside of girt then steel siding with no wrap or barrier. My thought is put Tyvek on inside of girt ( facing same direction as if on outside application ) then put inch and a half XPS DOW insulation against that ( because there’s two bunks already there) then 2×4 frame with batten insulation between them, then 6mil or heavier vapor barrier then OSB. The floor has PEX tubing in it but not hooked up. Is this a proper install?  Also I will have to have an engineer check the BCDL as I want to put OSB on the ceiling but would like to know how to insulate the ceiling. There is a one foot fully vented overhang with a ridge vent also. Thank You for the info in advance. 

Mike the Pole Barn Guru advises:

I am concerned about your building having an inch of XPS insulation between girts and siding. This allows screw shanks to flex, potentially creating slotting under screw heads and excessive deformation can result in your building cladding’s shear strength being compromised and (under extreme circumstances) racking enough to create a failure. I would feel much more comfortable if you were to add 7/16″ OSB or 1/2″ CDX plywood to the inside of girts in bays on each side of corner columns from splash plank to eave girt.

Moving forward….

Your external XPS is now acting as a vapor barrier (or close to it). Any exposed to inside seams should be taped. Do not put Tyvek on the inside of the girts, as this would allow any moisture in assembly to be trapped between it and XPS. Unless you already own a pile of 1-1/2″ Dow insulation, skip it and instead fill the balance of the wall cavity with rock wool or stone wool unfaced batts. Do not place a vapor barrier on the inside or seal OSB on the inside of the wall. Walls will now ‘dry’ to inside.

Provided your trusses are capable of supporting a ceiling, blow in fiberglass above your ceiling finish of choice. Make sure to allow at least an inch of air space above insulation at eaves so you get proper air intake from vented soffits. Unless you are very close to Canada and have at least 8000 heating degree days, do not add a vapor barrier at ceiling level.

Why Self Engineering is Risky

Reader MICHAEL in EAGLE POINT writes:

“I want to span 18 feet on a shed roof with any pitch necessary should I nail two 2x 6 rafters together and place this in the center and use 9 foot 2×6 purlins. The shed will be 18 X 18. Do I need to nail two 2×6 together for the two outside rafters?

All spans are clear span no center post The high side of shed is up against an existing building the low side will be new post and beam or posts with the rafters bolted to the post

This is a shed with only two walls. The existing high side as explained and the new post and beam side as the low side The two other sides will be open to drive under.

I plan on three or four posts on the low side depending on whether I use beams post to post underneath the rafters Or Bolt the rafters to either side of the post and eliminate the beams.

Since I’m using 2 x 6 purlins between the rafters I wondered if I could span the 18 foot length using two 2 by sixes (nailed together )For rafters. Since I’m using purlins I thought I could only have the rafters at each end and one in the center keeping in mind it is only a metal roof.”

Mike the Pole Barn Guru responds:
This sort of armchair ‘engineering’ is far too typical of what I read in social media groups.  When designs such as what is proposed are utilized, and buildings fail, folks are quick to point fingers as pole buildings being responsible, rather than lack of proper engineering design being our true culprit.

Please confirm this with your Registered Professional Engineer who will be sealing your building plans. Most of Oregon (your part included) has a minimum roof live load of 25 psf (pounds per square foot).  For sake of discussion, we will use 3 columns spaced nine foot on center along low and high sides and a five psf dead load (just in case someone decides to add plywood or OSB under a reroof some day).

Moment force = (25 + 5) psf x (9′ distance to next rafter / 2 [1/2 distance to next rafter] x 12″) x 18’^2 [ span of rafter] / ( 8 x 1.15 [Cd = duration of load for wood]) = 57,052.17 in-lbs

57,052.17 / (2 x 31.6406 [Section Modulus of a 2×12]) = 901.57 Fb [fiberstress in bending] required

2×12 #2 DougFir has a Fb of 900, so given bearing width at each end would most likely be approved by your engineer.

For rafters I would recommend a 2 ply 2×12 #2 DougFir on each end, and at center use two rafters on each side of the column. Connection at ends must be capable of withstanding 1215# so a single bolt will be nowhere near adequate (again, your engineer will properly design and detail this connection). Your thought of nailing two 2×6 together would be woefully inadequate (and would be over 300% over stressed probably failing during construction).

Hiring a Registered Professional Engineer is not an expense, it is an investment.

Market News: OSB Shortage

Market News: Oriented Strandboard Shortages

We are now living in a world of COVID induced product shortages – from commodities such as toilet paper, paper towels and cleaning products to simple things such as McCormick Thick and Zesty Spaghetti Sauce Mix.

When it comes to building products, it is not unheard of to have to wait three months for components such as windows and overhead doors!

Hansen Pole Buildings has a special relationship with Builders First Source, Inc. (www.bldr.com) . With 550 locations in 40 states, Builders First Source has an ability to provide near local deliveries to most of our clients. Largest lumber dealer in America, Builders First Source had 3rd quarter 2020 sales of 2.3 billion dollars!

Due to buying millions of board feet of lumber and countless thousands of prefabricated roof and floor trusses from them, we get some very preferential pricing treatment, allowing us to be competitive for our clients.

We also get insights into potential supply chain challenges – often before anyone else.

Brock Saxton is a Business Development Executive with Builders First Source. Previously he spent a dozen years with Carter®Lumber (a regional chain based in Kent, Ohio, with 146 locations in 12 states). This is his message to us:

“For future jobs it would be wise to avoid OSB. We are being told to be very hesitant about selling OSB and I foresee it being an issue for us if we need it.
Apparently the mills lacked production in Q1 to the point that the market is short 8,000 truckloads. One manufacturer is taking orders for Q3 which tells me it could get really interesting.

“If all the mills were running to capacity, the supply demand ratio reaches 100% right around 1.4 million housing starts. With a pace of 1.7 million and the lost production in Q1 the deficit is causing issues quicker than expected.”
I just want you guys to think about it.”

Checking prices at my closest The Home Depot® this morning saw 7/16” OSB at $25.70 a sheet and 15/32” (nominal ½”) CDX plywood was at $31.55 with an order of a full unit or more. Both products however have a limit of 90 sheets per order. While either of these prices may seem to be extreme – it will not matter if they become unavailable due to over demand.

Planning on taking advantage of those phenomenally low interest rates and putting up a new garage, shop or fully engineered post frame (pole barn) home in 2021? My best advice is to get happily involved sooner rather than later.

For extended reading on OSB and Plywood please see https://www.hansenpolebuildings.com/2013/10/osb-versus-plywood/

AdvanTech®

AdvanTech®

Christina reached out to me on social networking and asked:

“Hello, always look forward to your advice and I ran across something I didn’t find on the Hansen website. AdvanTech flooring as an alternative to OSB or plywood. Thoughts?”

While I have successfully utilized AdvanTech subflooring myself, rather than reinventing a wheel, today’s expert opinion comes from Matt Risinger (you may recognize him from www.buildshownetwork.com).

Matt writes:

When I started out in construction, I was working for a production builder. For many years, like most builders of that era, we used OSB (oriented strand board) subfloor — typically a 3/4-inch tongue and groove panel. There was no real choice in OSB then. It was whatever was available from the lumber supplier and we didn’t think a whole lot about it. We used a conventional construction adhesive and nailed off the floor, as that was the fastest method. But we had all kinds of squeaks on the houses we built. I thought that making the transition to screwing down the subfloor would be the answer to my squeak problems, but this didn’t help all that much. We still had frequent callbacks for squeaks. We also had a fair amount of edge swelling — an inevitable result of rain during the framing stage before we got the house dried in. That was a pain, too, because the swelling resulted in a wavy, bumpy floor that contributed to the squeak problems. Floor squeaks are the result of wood movement. Either a nail comes loose, or a screw shears off and you have up-and-down movement, or the edges swell and cause gaps beneath the underlayment that allow for creaks. Frequent callbacks did not do a lot for either the builder’s reputation or for the bottom line.

When I was working for a production builder, I didn’t really have much say in the purchase of materials, so I wasn’t able to change to a different subflooring product. Honestly, at that time, I did not really know there were other options. But when I started building custom homes about 12 years ago, one of the first changes I made was the switch to plywood. It was 1-1/8-inch plywood we should have glued to framing but just nailed it. This provided a nice stiff floor and eliminated my squeak issues. However, on one of my very first houses using plywood, we had a giant downpour during construction when the frame was open. This resulted in a ton of edge swell. Being a custom-built house, I had to fix it by sanding the edges and flattening the floor. The whole time the job was on pause for this to happen, all I could think was “OK, I love that I have eliminated squeaks. I love that I have a stronger, stiffer floor. But, man, this edge swell is a pain.” (And I hadn’t budgeted for the sanding either.)

I was looking for something better, but I thought “OSB? I’ve used that before and had problems. I’m not going back to that!” It was around that time, maybe 10 years ago that someone suggested I try AdvanTech subflooring.

I was soon to learn that there’s a big difference between AdvanTech panels and other subflooring options. Commodity OSB uses glues and a process that permits the panel to soak up moisture. Most subfloor-grade plywood uses similar glues between the laminators. While plywood gives you a more consistent panel, it is still prone to wicking moisture.

Plywood and OSB manufacturers try to improve this by sealing the panel edges, but the sealant, whether it is a wax or a paint, tends to get scuffed off. Think about how often panels get dragged on their edges across a truck bed or across the floor deck in the process of installing them.

Two things really distinguish how AdvanTech panels are made that contribute to their high performance over commodity OSB: resin technology and manufacturing precision. AdvanTech panels use an advanced liquid resin that coats flakes during the manufacturing process to make sure the panel is thoroughly protected. A lot of engineering and quality control goes into how the strands in AdvanTech panels are oriented and sized within the multiple layers to create a woven matrix of fibers that achieves the right balance of stiffness and dimensional stability. Commodity OSB is also set up in layers but can have larger variations in strand size and orientation within the layers and may use a different kind of resin that does not necessarily have the same moisture resistance. The AdvanTech subflooring manufacturing process also has a high level of precision to make sure the wood strands are the optimal thickness and dimension for a more stable panel. During manufacturing at AdvanTech panel mills, there are extensive quality control checks along the whole panel production process so that only the very best final boards earn the AdvanTech brand mark.

Once I made the switch to AdvanTech subflooring, I had zero edge swell, even with heavy rains during construction.

I’ve not had a single squeak and never had to sand edges down. That has been a huge change for me. I opt for the 1-1/8-inch panel on most of my projects because I want zero bounce in the floor. Certainly, I spend a little more on this subfloor than I have in the past. However, the elimination of problems makes it totally worth it. As with most materials choices, it’s never just about initial cost. Think about it: Not having to pay the unexpected costs of sanding, which interrupts the flow of the project, is one thing. But if I had to fix a squeak after the owners have taken possession and are living in the home, that is a nightmare. My business is based on an expectation of quality. Having no callbacks — having a much stronger, squeak-free floor — has made all the difference in being able to build a solid reputation for high-performing homes.

Having now gained some insight into AdvanTech’s benefits, it does come with some added investment. As compared to OSB subflooring AdvanTech will add roughly 75 to 90 cents per square foot of surface area (comparing nominal ¾” thickness products at current market prices).

Our Builder Has a Few Questions

Our Builder Has a Few Questions

Not a surprising statement, as few stick frame (stud wall) builders are willing to learn a new structural system, and few post frame builders have actually erected barndominiums or shouses (shop/houses).

I was a first group member (although willing to learn) and frankly lost my posterior financially erecting my first ‘pole barn’ because I had such a difficult time wrapping my head around left-to-right rather than up-and-down. I got my head on straight for building my second one and actually made $100 an hour back in 1980 erecting it!

For this second group, post frame home building takes in an entire new toolbox of concepts. Energy efficiency and ventilation concerns must be addressed, as well as a different set of efficiencies of material use. It is no longer just a ‘pole barn’  and requires a far greater degree of precision – it isn’t necessarily more difficult, but does take more thought.

Reader BRIAN in PETOSKEY writes:

Hi Mindi and Mike!

We’re really excited that we’re closing in on a final exterior design and starting to focus on the ‘fun stuff’ inside.

We shared the renderings and quote with our builder to keep him in the loop and he had some questions I wanted to share with you.

I’ve read your blogs and understand the argument for the truss arrangement that Hansen prefers. Trust me, I see the logic. That being said, he’s definitely one of those ‘trusses on 2′ centers’ kind of guys.

I explained all of the blog-based talking points on why it’s ‘better’. He was concerned that the material cost may be less, but the labor time would be significantly more to fill in between those spans with 2x10s, etc.

Furthermore, he usually covers the roof in OSB sheathing before putting on the metal. Is that included in this quote? Or is that something extra? He’s concerned about the logistics of applying the OSB with such wide spans between trusses. And in a similar vein, with drywall going on the full underside of all scissor trusses, he’s concerned about the additional lumber and labor needs to provide adequate hangers for sheetrock, etc.

And on top of that, he’s concerned about the lack of ventilation in the roof. I was under the impression that spray foam right onto the underside of the OSB for the entire roof was a best practice. He’s thinking we need baffles or something to allow airflow so as not to compromise the OSB over time.

So basically, a lot of questions on the construction logistics as it pertains to trusses and roof. Why not just run 31 scissor trusses on 24″ centers the length of the building and call it good? And how best to handle ventilation.

One comment he offered several times was that he understands the logic behind this construction style for a garage or storage building, but for a home with heat and sheetrock, etc. he thought this would be creating some obstacles for us.

If this is best answered via email, I’m happy to run middleman or add him as a CC on the answers. He also asked if Mike or someone from Hansen would be willing to talk to him on the phone? He’s open to the process, but wants to make sure he understands exactly what the construction process looks like. He said he would love to see a sample cross section or blueprint, but we both understand those are kept secret until we pay. He wants to wrap his head around it all.

One other concern was about wall framing. Some of the videos show horizontal studs as opposed to vertical. He wasn’t sure if that was always the case or if that is specific instances. Again, he’s a vertical stud kind of guy, but wants to understand if he can change that orientation or if it’s non-negotiable.

When it comes to truss space/between truss framing/wall framing, he’s definitely concerned about drywall logistics, OSB logistics (or not), moisture, and labor. And I want to make sure he feels heard and informed before we dump these plans and materials on his plate. I see both sides, but at the end of the day, he’s our builder and I need him to be fully on board before pulling the trigger. Could you help? I’m sure I’m not the first person with this quandary but I’ve also used enough pole barn builders in our area to know that he’s our best option for this project.

Thank you so much.

I see this dialogue as a parallel conversation to the design process. We’re forging ahead with design and working on our window and door placements this weekend.

Thank you!
Brian


Please tune in tomorrow for answers to Brian’s builder’s questions.

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.

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.

 

Truss Spacing for Shingled Roofs

Roof truss spacing seems to be a topic with no consensus. Most Americans live in traditional stick framed houses, apartments or condominiums, where roof trusses (if they were utilized, rather than using dimensional lumber rafters) are most typically spaced every two feet.

Reader CHARLIE writes:

“Dear Hansen Pole Buildings, May I ask how far apart was the Truss placement in your “Re-roofing with Shingles” article? 

https://www.hansenpolebuildings.com/2012/01/re-roofing-with-shingles/

I’m considering a 24’x 36’ pole barn for a recording studio build but would need asphalt shingle type roof. I’m concerned that a suitable design would need additional rafters to meet the 7 lb/sq ft load requirement.

Most designs I have seen are showing the trusses 4’ OC. 

Respectfully, Charlie”

Mike the Pole Barn Guru writes:
In this particular article roof trusses were actually spaced with a pair every 12 feet – directly aligned with sidewall columns. This style of post frame construction affords several advantages:

Fewer holes to dig. There is nothing more deflating than getting down to digging one or two last column (pole) holes and hitting a rock larger than a Volkswagon Beetle! Minimization of holes to be dug reduces chances of underground surprises.

No need for truss carriers (structural headers) between columns in order to support trusses. Structural failures are almost always due to connection issues. Truss carriers rarely have adequate fasteners from header to columns and trusses themselves are rarely anchored sufficiently to them.

By far my most read article of all time has been on pole barn truss spacing: https://www.hansenpolebuildings.com/2011/06/pole-barn-truss-spacing/.

Asphalt shingles need to be installed over asphalt impregnated paper (felt) or ice and snow shield, most usually over OSB (Oriented Strand Board) or plywood. Weak link of this system is spanning ability of this underlying sheathing.

In order to be within spanning capabilities of common sheathing, dimensional lumber roof purlins, on edge, were joist hung between truss pairs, every two feet.

When you order a post frame (pole barn) kit from Hansen Pole Buildings with asphalt shingles, we automatically have our engineers design for this added load, as well as reducing deflection criteria so you end up with a nice, smooth roof. We also take into consideration Building Code requirements to account for a future overlaid reroof (even “lifetime” shingles will not last anywhere near a lifetime).


Considering a shingled roof due to how long they are warranted? You might want to read this article first: https://www.hansenpolebuildings.com/2015/03/shingle-warranties/.

The Roof, The Roof… and Sheds without Sidewalls

Mike answers questions about a Roof Line, Roofing with OSB layer, and Endwall Only Sheds:

DEAR POLE BARN GURU: What is the roof line style in the attached picture called? BRYAN in MARYSVILLE

DEAR BRYAN: The prefabricated roof truss folks would refer to this as being a Polynesian roof – one in which the outer portion is at a lower slope than the center portion. I tend to steer clear of steeper-to-flatter roof slope changes as they just increase the possibility of a future leak, however it is certainly doable. Your photo also features a widow’s peak at the center.

 

DEAR POLE BARN GURU: Hello Guru, I am Putting 1/2″ Plywood On the trusses first before the metal roof, what do U recommend to cover the plywood, for vapor barrier protection? I was just gonna use felt paper! any recommendations? Thanx MIKE in ROCHESTER

DEAR MIKE: If applying the plywood directly over trusses spaced every two feet, you will need to add purlins in order to screw the roofing down (screws into plywood or OSB are inadequate for wind uplift). Steel manufacturers recommend the use of 30# asphalt impregnated paper (roofing felt) between sheathing and roofing.

DEAR POLE BARN GURU: What is it called if I only want a structure that has a wall in the front and wall in the back but open on the sides for animal pens? I can’t seem to find ANY images of this type of building. CHRISTINE in BERTRAM

DEAR CHRISTINE: I would call it a loafing shed with both eave sides open. It could be either single sloped, or have peaked endwalls.

Sometimes There Are Just Not Words: Hansen Building Disaster

Sometimes There Are Just Not Words to Express…  Building Disaster

How horrifically a build can be botched.

 

In a scene from 2013’s box office flop The Lone Ranger – Tonto (played by Johnny Depp) and the Lone Ranger (played by Armie Hammer) the heroes get themselves buried in the sand up to their necks. After looking at the photos provided by our client of what a “professional” builder did in framing his building, I am thinking tossing a coin to decide the builder’s fate might be appropriate. Heads – buried in the desert to the neck, or tails – boiled in scalding safflower oil (as we would not want the builder to meet his demise due to saturated fats).

These photos are of the front endwall of a Hansen building. The areas where the OSB (Oriented Strand Board) are visible are shearwalls. These are needed in order to carry the horizontal loads imposed on the building due to wind from the roof to the ground. In most cases, the steel siding is adequate to carry these loads. In this particular case, a large endwall door opening precludes this as a design solution.

In order to function as a shearwall the OSB has to be nailed on all edges, hence the 2×6 which is visible on the face of the columns. The engineered plans for this building happen to show the verticals as being 2×4, however this did not stop the builder from hacking up 2×6 which was ordained for somewhere else on the building. The trick to attaching the OSB at the edges (next to the columns) is to mount the provided 2×4 half onto the column, the other half projecting past the column so the OSB can nail to it.

Oops – ignored this part of the plan (and obviously never opened the Hansen Pole Buildings’ Construction Manual where this assembly is shown in step-by-step fashion).

But wait, it gets even better (or worse for the poor building owner)! Stay tuned tomorrow for the next installment .
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