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Vapor Barrier, Gothic Arch Truss Design, and a Lean-To Addition

This week the Pole Barn Guru addresses the need for a vapor barrier as well as some framing recommendations in a future build, the possibility of a Gothic Arch truss design with glulaminated columns, and the addition of a “lean-to” to a 2016 Hansen Building. 

DEAR POLE BARN GURU: Hello Mike, Our monitor style home has been designed by your staff and we are putting together financing and logistics details edging closer to ordering our materials package. Still a bunch of questions to ask of the Guru. We will be using an AIB under the steel siding with rockwool insulation in the cavities. I believe we will need a vapor barrier on the inside. I will be working alone on a lot of this construction and don’t look forward to wrestling with plastic sheeting for our vapor barrier. I would like to use a rigid insulation board such as r-tech or r-max with taped seams to accomplish this. I’m thinking it will much easier to seal electrical boxes and such with something rigid. What’s your take on this approach? Do you feel it is a safe and effective way to accomplish this? Thanks as always for your great information! RUSS in TILGHMAN

DEAR RUSS: Yes, you will need a vapor barrier on inside. I have suggested this very same solution more than once, as it looks like both reasonable to install and a way to minimize thermal transfer. I would recommend windows and door openings in commercially girted walls be framed out with one dimension larger members (2×10 rather than 2×8) and use 2 inch insulation boards, for ease of attaching finish trims on interior. You might also want to go with 2×8 treated bottom plates, for this very same reason. Insulation boards can be taped to these one size larger members.

 

DEAR POLE BARN GURU: Looking to use laminated Gothic arch design trusses, 4 foot on center anchored to 1st floor continuous floor trusses 16 inch on center with two rows of support beams at 12 foot under floor trusses. 2nd floor planning on recreation and residential area. Need to have plans drawn up to meet codes. Would this style post framing be sufficient for truss kick out using a truss bass shoe and steel gusset plate at ridge? Possibly add some knee walls at 1st floor framing for added support. Help me out, kinda designing on my own until I get prints. Thanks, ROGER in SOUTH HAVEN

DEAR ROGER: At one time I had actually acquired a set of plans for an old Gothic arch design. Tried to get them to engineer out and regardless of what lumber was used, could never get them to work. It might be possible to have glulams made to conform to your arch form, however I fear it would be phenomenally expensive. Should you be determined to follow this path, I would recommend you reach out to Travis at MSS Engineering (260)267-7414. He is registered in Michigan, and if anyone can make it work, it would be him. Best of success in your endeavor.

 

DEAR POLE BARN GURU: I purchased a 24′ x 36′ pole barn from Hansen in 2016. I has an 8′ lean-to on one eave side making its total dimensions 32 x 36. I would like to add a 10′ enclosed lean-to on the other eave side. Since my building is one of yours, can you design and price it with the same siding colors and account for snow load and the pitch of the new roof? KEVIN in FORT WAYNE

DEAR KEVIN: Absolutely we can assist you with this. One of our Building Designers will be reaching out to you Monday to discuss further. If you have enough available space, you may want to consider coming out 12 feet, as your investment will be very similar.

This entry was posted in Constructing a Pole Building, Post Frame Home, Pole Barn Planning, Barndominium, Trusses, Building Interior, Insulation, Budget, Pole Barn Questions, Sheds, Pole Barn Design, Building Styles and Designs, Pole Barn Homes, Roofing Materials and tagged , , , , , , on by .

Small Addition to House, Adding a Mezzanine, and Heating Options

This week the Pole Barn Guru answers reader questions about the addition of a small post frame building to a 1936 stick framed house, adding a mezzanine and lean-to, and a debate between radiant floor and forced air heating of a home.

DEAR POLE BARN GURU: I had a question from someone asking about a pole-frame addition to a 1936 stick-frame house. It would be small – under 500 s.f. and only a single-story. With the 2 different foundation and framing types, I am concerned about differential movement between the structures. I am not aware of any similar additions to other stick-framed homes so I am looking for previous examples that may have been done this way. Can the 2 structure types be connected, or should there be a movement joint between them? If a movement joint is required, I am only aware of joints for large commercial construction, like the 6-way seismic movement joints used in CA. MATT in PIERRE

DEAR MATT: Provided this addition is on undisturbed or properly compacted soils, column footings are adequate in diameter to support imposed loads (and reach frost depth or are frost protected), I would not expect to find ‘eye detectable’ differential movement between these two structures. As a builder in the 1990’s we erected several structures in similar situations and all have performed admirably now for three decades. I would encourage addition to be designed by a Registered Professional engineer and if soils are at all in question, a Geotechnical Report should be requested.

 

DEAR POLE BARN GURU: I bought a 30×48 kit from you last spring. It was delivered in September, 6 days before I left for a 6 month deployment in one of the not America countries we currently have a footprint in. I obviously didn’t get started on the garage but will be breaking ground as soon as I get home in April. Having 6 months to build the garage in my head has created some afterthoughts that I didn’t initially plan for. I would like to build a mezzanine in the back section between the end wall and the first set of trusses but would need to raise the ceiling in that first 12 feet to create enough headroom for the mezzanine. In my mind, I picture raising the ceiling joists to create a higher ceiling in that bay. Can the trusses support the ceiling if they are relocated or is the bottom chord the only part of the truss that is designed for the additional suspended load? Last question, If I want to add a lean to or a porch roof in the future, would Hansen be able to design it and sell me the materials like they did with the building? This wouldn’t happen for a few years, I just thought I would ask. Looking back, I probably should have added the lean to and porch roof to the original design but its too late to do that now! I honestly didn’t consider it before I spent the last 3 months looking at other garages online and seeing those features on other buildings. JOE in WOLFEBORO

DEAR JOE: Thank you for your service sir.

Mezzanine area – a challenge (finishing area to underside of roof purlins) is going to be insulation. As it will be impossible to create ventilation from eave-to-ridge between insulation and roof deck, it eliminates batts as a possibility and pushes your design solution to closed cell spray foam. As your roof steel has Dripstop to prevent condensation, chances are good this is not a proper surface to spray foam to. If your ceiling in this area will be other than light gauge steel, your roof purlins will not be stiff enough to resist undue deflection. Ceiling joists in this last 12′ bay could be omitted to allow for adequate headroom, provided x bracing remains in place. If this mezzanine will be supported by your building columns, it is very possible column footings will be overloaded.

Yes, we can provide a lean to or porch addition at any future date. Any current building footings, that might support this addition, should best be increased in diameter by at least six inches, to account for weight of future addition.

 

DEAR POLE BARN GURU: Long time reader here. Hoping you can help me make a decision on something. We are building a pole barn home very soon and I’m struggling with deciding between in floor radiant heat and forced air. Obviously radiant is more even and more efficient but also costs more up front. If we did forced air, would we have moisture problems on the concrete floor? Just really torn and would like your opinion on which to use. If we go radiant we will use mini splits with ceiling cassettes for cooling. Thanks MARC in AUBURN

DEAR MARC: Thank you so much for being a loyal reader! Our post frame home has radiant floor heat downstairs and I couldn’t be happier with it. Nothing like warm concrete. Regardless of how you heat and cool, you should use at least R-10 rigid insulation under (and at edges of) your slab, as well as having a vapor barrier underneath. How you insulate will also play into this – if you closed cell spray foam perimeter, then you will have to mechanically dehumidify, else you are going to experience moisture issues. Reach out to my friends at www.RadiantOutfitters.com for your floor heat, they know their stuff and will treat you right.

This entry was posted in Ventilation, Pole Barn Heating, Concrete, Footings, Barndominium, Lumber, Building Interior, Insulation, Budget, Pole Barn Questions, Pole Barn Design, Columns, Constructing a Pole Building, Lofts, Pole Building How To Guides, Pole Barn Planning, Pole Barn Homes, Trusses and tagged , , , , , on by .

Adding a Lean-to aka Side Shed

Adding a Lean-to aka Side Shed

Reader PATRICK in REDMOND writes: “I have an existing pole barn that was built in 1999 that I would like to add a lean-to onto. I read your previous blogs about verifying the footing that supports the existing poles – but how do you verify that? Is there a way to inspect that? Your previous blog also stated if the trusses are supported by truss carriers(which mine are) then then the trusses could not support extending the roof(I think I read that correctly) if I wanted to drop my lean-to roof line below the existing roof line would still be a concern? Thank you.”

Thank you for your photos.

In order to verify actual diameter of your footings, if your building has holes entirely filled with concrete, you could measure across top of concrete encasement at ground level. If holes were backfilled with compacted soil, sand or rock, it would take having to excavate along outside of a column until footing was reached and measure across it.

In your instance, trusses are not bearing on truss carriers, but rather bearing blocks placed below truss heels, on each side of columns.

If you drop top end of lean-to below existing eave height, you need to account for added weight of snow slide off and drifting. This can result in larger dimension and/or higher grade lumber being required in order to carry this extra weight.

We can engineer and provide your plans and materials for your lean-to, knowing all of this information below:

Information from your Building Department (listed in these two articles): https://www.hansenpolebuildings.com/2020/08/building-department-checklist-part-i/ https://www.hansenpolebuildings.com/2020/08/building-department-checklist-2020-part-ii/

While we have this information on file from most jurisdictions, we always want to have it verified before you get to deep into your project.

Width (span) of existing building from outside of column to outside of column. Length of existing building
Existing building sidewall column spacing
Existing building eave height (https://www.hansenpolebuildings.com/2017/10/rehashing-eave-height/)
Existing building roof slope
Existing building column footing diameter
Any overhangs
Will high end of lean-to be at eave height of existing building, or lower? If lower, how much? Width of lean-to Any low eave or endwall overhangs

One of our Building Design team members will be reaching out to you to further discuss your building wants and needs.

This entry was posted in Pole Barn Planning, Barndominium, Concrete, Lumber, Rebuilding Structures, Pole Barn Questions, Pole Barn Design, Columns, Building Styles and Designs, Sheds, Building Department, Constructing a Pole Building, Pole Barn Homes, Pole Building How To Guides and tagged , , , , , on by .

The Shell or Interior, an Old Barn Fix, and Ventilation

Today’s Pole Barn Guru answers reader questions about inclusions of a Hansen Building Kit, some guidance with the renovation of an old barn, and how many sq inches of NFVA do foam enclosures have?

DEAR POLE BARN GURU: What does it include? Just the shell or interior also? ASHLEY in MONROE

DEAR ASHLEY: We typically provide detailed engineered plans, all verifying structural calculations, step-by-step installation instructions and materials delivered to your site for complete building shells (including doors and windows), as well as any raised wood floors and stairs. Interior stud walls (to create rooms) are usually best acquired from any nearby lumber supplier, as they are non-structural and do not support any roof or exterior wall loads. While we have provided interior wall materials, since we only send our clients very high graded lumber, it is typically not your most economical design solution.

 

DEAR POLE BARN GURU: I have an old barn, built early 1900s. A lean-to was added somewhere in the 60s. The barn is collapsing but the lean-to part is still good, size 36×24. I want to add a new posts and header for the rafters replacing the barn wall 36′ length. I plan to use wet set brackets and 6x6x16 post. I am not able to set post in the ground without removing the roof. Is 4 poles with 12′ spacing enough support? The barn, what’s left will be removed afterwards leaving an open side to put equipment in an out. DOUGLAS in TIPTON

DEAR DOUGLAS: Adequacy of those columns is going to depend entirely upon actual dimensions of your 6×6 columns, their grade and species, roof height, design wind speed and wind exposure, roof snow load, type of roofing and siding (both for weight and deflection purposes), among just a few determining factors. While what you have may very well be adequate, you should reach out to a Registered Professional Engineer to verify. Travis McDaniel of MSS Engineering is based in Indiana and would be an excellent choice to contact, as he has extensive post frame (pole barn) experience. His number is (574)855-6131.

 

vented-closure-stripDEAR POLE BARN GURU: Pole barn has metal roof with ridge vent and vented foam enclosures. How many sq inches of NFVA do foam enclosures have? TOM in ROYAL

DEAR TOM: It will depend entirely upon what brand of vented foam closures you have. We provide a Marco LP-2™ ridge vent (read more here: https://www.hansenpolebuildings.com/2014/12/ridge-vent/ with 18.4 square inches of net free ventilation per lineal foot of ridge when placed on each side of ridge, provided roof steel’s upper edges from each side are at least 1-9/16” apart.

This entry was posted in Ventilation, Building Interior, Lumber, Professional Engineer, Pole Barn Questions, Columns, Pole Barn Design, Building Styles and Designs, Barndominium, Building Department, Roofing Materials, floorplans, Pole Barn Planning and tagged , , , , , , , , on by .

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 Trusses, Ventilation, floorplans, Building Interior, Budget, Insulation, Professional Engineer, Pole Barn Questions, Columns, Pole Barn Design, Sheds, Roofing Materials, Pole Barn Planning, Barndominium and tagged , , , , , on by .

Electrical Poles, Adding an Awning, and Sliding Door “Overlap”

This week Mike the Pole Barn Guru answers reader questions about the practical use of “electrical poles” for the addition of a lean-to to a garage, adding a door awning to a pole barn kit, and how much overlap a sliding door will have around the perimeter.

DEAR POLE BARN GURU: If I add a lean to on to my garage 18 x24,/ 24 foot side. Electrical poles 6 feet out of ground 8ft away. Add 2x 6 trusses and purlin on top of that. How do I attach the 2×6 to the round pole? SUE in HINCKLEY

DEAR SUE: We would never recommend or suggest utility poles be used for post-frame construction, for a plethora of reasons. Here is some extended reading:

Reasons to Buy Used Utility Poles for Pole Barns

 

DEAR POLE BARN GURU: I’m having a 36′ x 36′ pole barn built from your kit. It has an entry door. Do you sell a door awning that will fit securely to the wall siding? I don’t want the awning to leak up against the wall. Thanks. ROGER

DEAR ROGER: Bad news is – whomever is erecting your building may have told you it would be one of our buildings, however it is not. We have had contractors do this in past years, only for there to be problems later, clients called us only to find out it was not what they believed they had invested in. Sadly, you will not have our industry leading limited Lifetime Structural Warranty. For our buildings we do offer a wide variety of weather tight entry door covers, both self-supporting and pole supported. These can have single sloped, gabled or hipped roofs to meet our client’s needs. We are unable to provide any of these choices for buildings other than ours.

 

DEAR POLE BARN GURU: Hello, I have a question. If you have time to answer. If the rough opening of a sliding door is 20′ x 14′. How much overlap should the doors have when closed? As in on the top and outer sides? I have tried looking at your site, and every other site on the internet. I am seeing maybe 3/4″ on top and the outer sides. Of course the center of the doors meet in the middle. Would the 2 doors be something like 10′ 1″ x 14’1″ Or bigger? Thank You, JOE

DEAR JOE: Typically for a 20′ wide x 14′ tall split sliding door, with top mounted track, from grade (bottom of pressure treated splash plank) to bottom of 2×6 track board (mounts on face of door header) will be 14′ 4-1/2″. 20′ width is measured from center of post to center of post on each side. Working from these dimensions, each door leaf will be 10′ wide x 14′ tall. Space between track board and top of sliding door will be roughly 1/2″ (this will be covered by sliding door track cover trim). Bottom of door will be roughly 1/2″ above top of a nominal 4″ concrete slab (3-1/2″ actual). Each extreme outside edge will overlap wall by ½ width of column on each side.

This entry was posted in Pole Barn Planning, Pole Barn Structure, Pole Building Doors, Rebuilding Structures, Porches, Sliding Doors, Pole Barn Questions, Pole Barn Design and tagged , , , , , , , , on by .

Steel Posts, a Pole Barn Conversion, and Column Size

This week the Pole Barn Guru answers reader questions about the use of steel posts for a lean-to, converting an existing pole barn with an open wall into a one-bedroom tiny home, and columns for a post frame remodel and addition.

DEAR POLE BARN GURU: I’m building a lean to up against my 40′ high cube container using 11′ galvanized steel posts that are 2 3/8″ diameter at 13ga. Poles are set in concrete at 3′ and plan to set 7 poles every 6′ on center for a total span of 36′ from center of each end post. Will be using 2×10 treated wood for rafters and 2×4 treated wood for purlins.

My question is are 7 poles every 6′ center overkill or can I get away with 5 poles. Roof will be 26ga. Galvalume.
Thanks,
DAVID

DEAR DAVID: I personally would not attempt to build any structure based upon steel posts. You really should invest in services of a Registered Professional Engineer, who could give you answers you can hang your hat on. Much better than waking up one morning and finding your lean to either flat on ground, or blown away into your neighbor’s yard.

 

DEAR POLE BARN GURU: We have a 22′ by 32′ pole barn with 3 metal sides, front open no flooring. We would like to turn into a 1 bedroom tiny home for our daughter. Can it be done without breaking the bank? STEVE in EFGEFIELD

26x40 Pole BarnDEAR STEVE: Before you get too deeply into this, you really should engage a Registered Professional Engineer to visit your building to determine if it is structurally capable of being converted for residential use. Most pole barns are not designed to residential standards, so your engineer can advise as to what repairs/upgrades will need to be made.
Typically fully engineered post frame, modest tastes, totally DIY, move in ready, budget roughly $70-80 per square foot of floor space for living areas. Does not include bringing in utilities or any permits.

 

DEAR POLE BARN GURU: We have a future project coming up and the customer wants us to take half a existing building and take it from a 9′ side wall to a 16′ sidewall. My question would be should we use the existing laminated column and just off set the joints or remove the posts and start fresh for that half? CHANCE in CASPER

DEAR CHANCE: You will want to place a new set of columns for this taller eave portion, both from a practicality standpoint, as well as liability. Any time you structurally tie into an existing building, you now become liable for any failures associated with it, whether you actually has anything to do with it or not.

Also – maybe consider rotating roofline of taller portion by 90 degrees to keep weather (e.g. snow) from dumping off in front of new overhead door.

This entry was posted in Constructing a Pole Building, Pole Barn Planning, Columns, Pole Barn Homes, Pole Barn Questions, Pole Barn Design, Building Styles and Designs and tagged , , , , on by .

Rafter Size, Lean-to on Slab, and “Barndominium?”

This Wednesday the Pole Barn Guru tackles questions regarding rafter size for a lean-to addition, adding a Lean-to to an existing building on a monolithic slab, and “the difference between a pole barn home and a barndominium?”

DEAR POLE BARN GURU: I am building a lean-to on an existing pole barn. It is 32′ long and it will be 14′ wide on a 3/12 pitch The posts are 8 ft on center. My question is what size rafter do I need to span 14′ at 8′ on center with 2×4 purlins on edge? Thanks. MICHAEL in LIZTON

DEAR MICHAEL: A caution – if your shed roof ties in at any height other than exactly at eave, or is not at same slope as existing roof, you have a snow slide off/drift load to contend with and are best to engage an engineer to account for this extra loading. An exception would be if you have a snow retention system on your existing roof. Assuming above is not an issue, please read on. As I do not know your loads, you can fill in blanks in this formula to find out: (roof live load + roof dead load) x spacing (in your instance 96″) x span in feet squared (14′ squared for you). Divide this answer by: 8 x Rafter Section Modulus x Fb (fiberstress in bending of lumber proposed to be used) x 1.15 (duration of load for snow) If your result is 1.0 or less, then you are golden. Section Modulus is depth of member squared x width of member divided by 6 Example : 2×12 = 11.25″^2 x 1.5″ / 6 = 31.64 Fb for #2 grade Southern Pine will be 2×8 = 925; 2×10 = 800; 2×12 = 750

 

DEAR POLE BARN GURU: Can I build a pole lean-to and attach it to my shop that is built on a monolithic slab? I did not intent to put a concrete floor in the lean-to. Can I do this without pouring a foundation for the lean-to? The Lean-To will be 50′ by 16′ with metal sides and roof. Thank you. GLEN in HYSHAM

DEAR GLEN: Maybe, provided your existing building footings are adequate to support weight you will be adding. Easiest and safest way is to set a row of columns directly alongside existing building wall, so you can treat new structure as being self-supporting. You will not have to pour a foundation, you can auger holes, place UC-4B pressure treated columns in holes, then backfill bottom 16-18″ with premix concrete to create a bottom collar. If your new lean-to has a pitch break, or is lower than main roof on high side, you do need to account for weight of slide off/drifting snow onto it. This can be avoided, by installing a snow retention system on your existing roof.

 

DEAR POLE BARN GURU: What is the difference between a pole barn home and a barndominium? SHARON in WESTCLIFFE

DEAR SHARON: Barndominium is pretty much a made-up term, with no recognized or official description. For sake of discussion, any pole barn (technically post frame) home would be a barndominium, while barndominiums could also be other structural systems with a ‘barn like’ look and most often steel roofing and siding.

This entry was posted in Pole Barn Homes, Pole Barn Questions, Pole Barn Design, Building Styles and Designs, Constructing a Pole Building, Barndominium, Pole Barn Planning, Concrete, Footings, Columns and tagged , , , , , , , on by .

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 , , , , , , , on by .

Providing Digitally Signed Structural Plans in Florida

Providing Digitally Signed Structural Plans in Florida
Reader JEFF in TAMPA writes:

“Have an existing slab approx. 12×20 and slightly out of square on 7 acres of land. Want to erect a simple, square (approx. 13×21), hip-roofed (5/12 pitch) pole barn over the slab with two lean-to, open carports on either side (pictures of layout attached). Can you provide digitally signed plans for county permit authorities in Hillsborough county (must be signed by a P.E., architect or other professional licensed in Florida)? If yes, let me know the approximate cost. Thank you. Plan to use glulaminated pressure-treated lumber (12′) 3 ply 2×6 lumber for the 20 poles if I can them in Florida.”

Hansen Pole Buildings has provided thousands upon thousands of fully engineered post-frame buildings in all 50 states, including roughly a hundred to our clients across Florida.

Your layout pictures Jeff, sadly did not make it.

While full hipped roofs are lovely, they do not often lend themselves well to adding lean-tos, especially if the building has endwall overhangs (transition at hip corner to lean-to single slope becomes ‘messy’).. You may end up being best served by considering a 21 foot span gabled roof, all at the same eave height. Center portion could easily be enclosed with open carports at each end. This also provides for greater clear height under roof only areas.

We can certainly provide fully engineered plans, digitally signed by one of our experienced third-party Florida engineers and they will be included as part of your investment in your new Hansen Pole Building (and yes we can include true glu-laminated building columns). Our engineers will only seal plans when we are providing materials, as some of what they specify is proprietary to us and there is no way to guarantee an alternative supplier will actually deliver them.

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Adding a New Lean-to

Adding a Lean-To Shed on an Existing Pole Barn

Reader SAM in CANNON FALLS writes:

Pole barn garage“Hello I am looking to add a lean-to to the side of my pole building on the eave side. I was looking to use a mono truss at with a 2/12 pitch and 8′ to the bottom of the truss/ ceiling height. Existing pole building has 6×6 posts with an 8′ on center spacing. The lean to is going to be 24′ wide by 10′ deep with 4 posts and a beam at the 8′ mark (so it would have a 2′ overhang. to connect it to the existing building we were planning on installing a ledger on to the 4 6×6 post on the existing building to hang the mono trusses off of. My question is do I need more posts on the existing building side and truss spacing or what would you recommend for my application.”

Your situation is one seemingly quite simple, however is fraught with potential for creating more structural problems than it resolves.

Here are some general considerations when adding a side shed:

Inadequate footings

Most (especially ones not designed by a Registered Professional Engineer) post-frame buildings have inadequate footing under their building columns. Often this is a result of having been built by a “professional” builder who sees cheaping out here resulting in adding profit to their bottom line. Use of dry bags of premix (https://www.hansenpolebuildings.com/2012/11/concrete/) or inadequately sized concrete ‘cookies’ fall into this category. If your intent is to attach to existing building columns, then an engineer should be consulted to verify adequacy of existing footings for weight of present building and planned addition.

Drift/Slide off loads

If the high side of your proposed addition is lower than the main building eave, then snow will slide off onto your new shed roof. This can easily result in loads being imposed on new roof system far beyond the design capacity of roof purlins and trusses. In some instances, snow slide off can be great enough to actually fail steel roofing! https://www.hansenpolebuildings.com/2015/05/monitor/

What if the high side of shed and the low eave of the original building are at the same height? Doesn’t this solve potential snow problems?

Well, in a word, no. Now snow has a greater surface to accumulate on (one half of main roof plus added shed roof). When winds blow across the shed and up the main roof, they now deposit a greater pile of snow upon the leeward side of the roof near the peak. While all trusses are (by Code) supposed to be designed to support unbalanced snow loads, there is no way this extra load could have been anticipated – potentially leading to a failure of your main building trusses.

This particular scenario can also result in leaks, if not properly framed and carefully flashed – https://www.hansenpolebuildings.com/2014/10/pitch-break/

Moving on to your proposal…

For an eight foot span from the main building wall to the new row of columns, ordering prefabricated roof trusses is going to be an expensive proposition. Although I love prefab trusses (I spent two decades in this industry, in a past life), unless you intend to create a flat, level ceiling in this shed, it just isn’t worth it. Dimensional lumber rafters are most likely your best option.

A 2/12 roof slope may not be your best choice. Most steel warranties are void on roof slopes under 3/12. Building Codes require sealant tape to be used between under and over laps with steel roofing (again adding to degree of difficulty).

Ledger boards are rarely adequately attached to resist imposed loads (remember snow).

If it was my own building – I would hire an engineer to verify adequacy of design. Provided footings were (or could be made) adequate, I would remove sidewall steel from the main building, so rafters could be attached directly to existing wall columns. Then reinstall steel using J Channel around where rafters protrude through the wall. I would hope to use a single rafter on each end, and one each side of existing columns. Roof purlins would be placed on edge between rafters – joist hung to interior ones and over top of end rafters if there is an end overhang.

Lots of considerations here and you have only a single opportunity to do it right or wrong. Best of success to you.

This entry was posted in Building Overhangs, Trusses, Concrete Cookie, Footings, Columns, Sheds, Pole Barn Questions and tagged , , , , , , on by .

Occupancy, a Single-Slope Residence, and Lean-to Addition

This week the Pole Barn Guru take care of reader questions about getting an occupancy permit in Victor ID, the size and scope of building a single-slope with a loft, and the addition of a lean-to to an existing structure.

DEAR POLE BARN GURU: I follow your posts and have seen some who question if a pole building can be built as a home and get an occupancy permit. I have some property in Victor Idaho, Teton County Idaho building department. My question is: Can I build a small (about 1200 square feet) building in Teton County Idaho and get an occupancy permit to live in it? Thanks! AL in SURPRISE

DEAR AL: My first experience with Teton County was nearly 30 years ago – when, as a General Contractor, we built a post frame building for Driggs Plumbing. Fully engineered post frame buildings are 100% Code conforming structures and when designed appropriately for Risk Category II and a R-3 (residential) occupancy they make for excellent homes. I have read through Teton County’s Building Department information online and see no minimum footprint requirements for homes, however you would be best served to give a call to Teton County’s Planning and Zoning Department at 208.354.2593. https://www.hansenpolebuildings.com/2020/01/your-barndominiums-planning-department/

 

DEAR POLE BARN GURU: Hello. We are in the planning stages of designing our home and are thinking of building a 40×60, single slope home with a loft on the tall side. Have you ever designed anything like this? I am having a hard time figuring out what height walls I would need and what pitch roof in order to accommodate a loft. I am thinking that i would like 10’ ceilings and 8’ ceiling for the loft, but worried that being vaulted, I will lose usable room space fast. Please let me know if you can help. Thanks! NATE in BIXBY

DEAR NATE: For sake of discussion, let’s work from a 12′ loft width. Allowing for your requested ceiling heights at low side of loft, and thickness of floor and roof system, a 22′ height is not unrealistic at this point. With a 3/12 roof slope (typically a minimum to prevent voiding roof steel paint warranty) your eave heights would be 25′ down to 15′.

 

DEAR POLE BARN GURU: How to tie a self-supporting lean-to onto my existing pole building? Ham Lake city inspector said my existing pole building footings don’t support the added weight of a lean-to and therefore need posts on the high side of the lean-to. Pole Building is 30×64. Lean-to is 19×64. Ham Lake inspector says you don’t need to tie the buildings together other than the lean-to roof tucked underneath the existing roof. The 9 posts on the high side lean-to will be 1′ away from the existing 9 post on the Pole Building. I want to tie these two posts together. I’m thinking of cutting a hole in the siding and nailing a 2×6 onto each post at the top somewhere. Do you have any suggestions? Thanks. KEITH in HAM LAKE

DEAR KEITH: Your Building Inspector is absolutely correct. I see far too many cases similar to yours where a lean-to is added onto an existing building and due to inadequate footings results in an up-and-down roofline. Not certain why you would want to go through efforts of trying to connect those columns, and any meaningful connection could result in loads being inadvertently transferred between buildings. To me, it sounds like more work and efforts than it could ever be worth. We had this very same situation when we added a 30′ x 96′ lean-to to our 96′ x 96′ warehouse. We did not tie columns together and have never experienced any sort of negative challenges from it.

 

 

This entry was posted in Pole Barn Homes, single slope, Pole Barn Questions, Pole Barn Design, Post Frame Home, Building Styles and Designs, Barndominium, Building Department, Constructing a Pole Building, Pole Barn Planning, Professional Engineer, Columns and tagged , , , , , , on by .

Making Everything Fit Under an Attached Lean-To

Reader GEOFF in MILFORD has an often found potential challenge, he writes:

“I am looking to build a 30×40 pole barn and want to also have a covered lean to for my camper that will run the length of the barn. In order to have the lean to tall enough for the camper how tall do I need to make the peak of the barn? I need at least 11 feet of height under the roof truss to make the camper fit. My thought is that I should be able to make the barn tall enough to just extend the roof out at the same pitch to cover the lean to. But at the same time I don’t want to make the barn taller than I need to make it. 

Hope this makes sense 

Thank you”

Mike the Pole Barn Guru responds:

Yours is a frequently seen dilemma – trying to fit tall things under an attached side shed (lean to). Even worse, when a future situation arises and a shed addition is needed and main building walls were just not tall enough to make everything work comfortably and not have a very low slope shed roof.

Rather than having to make your enclosed building portion significantly taller, I would recommend you approach this with an idea of it basically being a 40 foot square building, with one sidewall ‘pulled in’ 10′. If you went with say a 13 foot eave height, you could have 12 feet of interior clear height both inside, as well as under your roof only portion. This will allow for plenty of headroom both inside (where you could have a vehicle lift) and outside for your camper. With a 4:12 roof slope your overall building height would be 19’8″ under this scenario.

Most folks would take a design approach of trying to work this as a side shed. With a 13 foot eave height on the low side of a 10 foot width shed, at the same 4:12 roof slope, your eave height of enclosed portion would need to be 16’6” making overall building height 21’6”!

This entry was posted in RV Storage, Pole Barn Questions, Pole Barn Design, Pole Barn Planning, Sheds and tagged , , , , on by .

Ladder Framing, Use of Red Cedar Posts, and Custom Steel Trusses

This Monday the Pole barn Guru answers reader questions about “ladder framing,” aka bookshelf girts, the use of Eastern Red Cedar posts in post frame construction, and if Hansen provides custom steel trusses.

DEAR POLE BARN GURU: I had a question about ladder framing on a finish shop. I was thinking about running my two by sixes horizontally between my poles. So I could insulate them horizontally with 24 inch batt insulation. Then I wouldn’t have to add nailers on the inside for when I finish it. What’s your opinion? Thank you. DAVID

DEAR DAVID: I am a huge advocate of using commercial bookshelf style wall girts for any post frame building where climate control might be anticipated. Bookshelf girts also lend themselves well to best possible application of sheetrock.

For extended reading on this subject please see https://www.hansenpolebuildings.com/2017/08/bookshelf-girts-insulation/.

 

DEAR POLE BARN GURU: Greetings. We are looking at building a 40’x60′ pavilion. We live in Missouri and are overrun with Eastern Red Cedar. We have used them for posts before for porches and the like. I was wondering if a 10-12″ ERC would work as a post for a pole barn with a 10’roof and double truss construction. ROGER in IRONDALE

DEAR ROGER: Untreated Cedar, left exposed to weather in above ground situations probably has an expected lifespan of roughly 10 years (https://www.fs.fed.us/t-d/bridges/documents/tdbp/decayres.pdf). While you may have better results, it is not something I would or could recommend when properly pressure preservative treated columns are readily available and will outlast any of our lifetimes.

 

DEAR POLE BARN GURU: Hi, I’m putting a leanto on my barn, and I need 4 custom steel trusses.  Do you build and deliver custom trusses or only whole building kits?  The trusses would be ~19′ long for a 39’x19′ roof.  I live in Pennsylvania. KEITH in NEWTOWN

DEAR KEITH: Thank you very much for your interest in a new Hansen Pole Building. We do not use steel trusses in any of our buildings, however it is very possible we could provide a similar design solution using prefabricated metal plate connected wood trusses.

 

This entry was posted in Lumber, Pole Barn Design, Constructing a Pole Building, Pole Barn Planning, Trusses, Columns and tagged , , , , , , on by .

What Kind of Trusses Are Pictured?

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 Questions, Pole Barn Design, Building Overhangs, Pole Barn Structure, Trusses and tagged , , , , , on by .

What Size Post Spacing?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: Building a 32’x 50′ barn that’s 32′ high. Trying to determine the extension out from the ridge for the widow’s peak/ hay hood. Didn’t know if there’s a correct mathematical equation for this? PHILIP IN NEW KNOXVILLE

DEAR PHILIP: There is some mathematics involved, but it comes from a structural standpoint, rather than aesthetics.

A widow’s peak is an extended pointed overhang placed in the center end of a barn roof. Historically, they were used as a pulley support to raise hay bales into hay lofts. In modern post frame construction, very few widow’s peaks are actually used functionally, other than as shelter to protect a loft door. More often than not, they are strictly for aesthetics.

The width of the widow’s peak is usually 1/3rd to ¼ of the width of the gabled end of the building. The distance extended beyond the building endwall, or other endwall overhang is up to the eyes of the beholder, but is most typically three feet.

Now for the math…..the roof surface of the widow’s peak must be accounted for in the design of the endwall truss, as well as the supporting roof purlins. The truss manufacturer needs to be aware of the dimensions of any overhangs beyond the end of the building. The supporting roof purlins can be capably designed by the RDP (Registered Design Professional – architect or engineer) who has done the building design. The nicest looking widow’s peak at time of construction, can end up being far less than pretty if it sags over time.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: What is your typical post spacing and what is the maximum spacing the poles can be spread out? RICK IN WATERLOO

DEAR RICK: The most efficient post spacing is going to depend upon the wind and snow load conditions at any particular given pole building site. As a general rule, the best “bang for your buck” is most typically spaced every 12 feet, although 10 foot and 14 foot spacings are often a close second.

On fully enclosed buildings, the wall girts normally become the dictate on how far apart columns can be placed – they usually will fail at 16 foot pole spacing (again, depending upon wind loads).

For buildings where one or more sidewalls are partially enclosed, 24 foot spacings between columns can be fairly easily accomplished. On endwalls, with a clearspan truss, it is possible to have posts only at the building corners.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: Does Macomb Township allow pole barn construction for a garage? Do you work in Macomb Township, MI? PETE IN MACOMB

DEAR PETE: Pole barn (more technically “post frame”) construction is a 100% code conforming construction system. I’ve found jurisdictions which have tried to prevent “pole barn” construction within their jurisdictions, and we have successfully won the battle every time. Jurisdictions can legislate what a building looks like, however it would be improper to attempt to limit a conforming structural system.

Should you (or any other reader) find a jurisdiction which has contrary ideas, please let me know – as I will have a friendly (and persuasive) discussion with the jurisdiction’s legal counsel.

Macomb Township does have an unusual requirement for any type of building – “rat walls”. You can read more about them here: https://www.hansenpolebuildings.com/2012/06/rat-wall/

As to where we do work, Hansen Pole Buildings provides complete custom designed pole building kit packages anywhere in the United States – including Macomb Township.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I want to add a lean-to on my 42 x 48 pole building. Should I attach 2×10’s to the poles and put purlins on top of them as if continuation of the building, or should I put a ledger across the side and build accordingly. Thanks DION IN RUHKAMP

DEAR DION: Your cart may be slightly ahead of your horse. Before looking at the rafters and purlins, it might be a good idea to read: https://www.hansenpolebuildings.com/2015/07/shed/

Back to your original question – I personally prefer to attach the rafters directly to the columns with roof purlins on edge in between the rafters. As to 2×10’s – depending upon the width of the shed and your snow load, it is not likely they are adequate. With more information, I can give you a more definitive answer.

Mike the Pole Barn Guru

This entry was posted in Pole Barn Questions, Pole Barn Planning, Pole Barn Structure and tagged , , , on by .
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