Tag Archives: Post size

Frustrating Builder, Post Size, and Sliding Barn Doors?

This week the Pole Barn Guru tackles reader questions about recourse against a builder that “never does what what he says,” a question about the necessary post size for an RV shelter, and the need for a structural engineer to answer the question, and advice for a reader whose doors blow out wondering if sliding doors are the solution— probably not.

DEAR POLE BARN GURU: Thanks, I have a builder who has not done one thing right. The details are long and frustrating. What recourse do I have? It seems there is no codes in Heavner, Oklahoma I would like to send some pictures. I am disabled and to not have stress. This guy lies and never does what he says. Never got a contract, asked several times. KENETH in HEAVNER

DEAR KENNETH: Hire a Construction Attorney Now.

Do not give this builder any more money.

You have probably now realized you have committed a cardinal sin of building construction – hiring a builder, without a contract.
For those of you following along at home: ALWAYS THOROUGHLY VET ANY CONTRACTOR https://www.hansenpolebuildings.com/2018/04/vetting-building-contractor/
And contracts are boring, until you go to court: https://www.hansenpolebuildings.com/2021/06/contracts-are-boring-until-you-go-to-court/

 

DEAR POLE BARN GURU: What size post needed for 26 by 26 with 12 foot high wall and 4/12 beam roof RV port. DON in OMAHA

DEAR DON: This is a question best answered by an engineer who is going to seal your building plans (whomever you are purchasing your building kit should be including them). While I cannot give you actual engineering advice, I can tell you what will not work.

In a roof only post frame building, columns act as cantilevers (think diving board). There is a minimum column dimension calculation, based upon a column’s unsupported length. In most cases, this unsupported length is from top of full concrete backfilled hole, to bottom of roof trusses.

Let’s take a look at a 6×6 (actual dimensions of 5-1/2″ x 5-1/2″). The L/d (Unsupported length divided by least dimension of column) ratio must be less than 50. 12 feet equals 144 inches, so 144 divided by 5.5 equals 26.18 – but, NOT SO FAST, columns are also impacted by a ‘magical’ factor known as Ke. For a purely cantilevered column Ke is equal to 2.1. Therefore 26.8 times 2.1 equals 54.98, as this is greater than 50 and a 6×6 would fail.

Greatest unsupported length of a cantilevered 6×6 column would be 130.95 inches. This does NOT take into account loads having to be carried by this column (snow, wind and seismic), hence your need for an engineer to verify structural adequacy.

 

DEAR POLE BARN GURU: I’ve had my 2, 12 x 12 panel doors blow out and my roof dropped 1/4 mile away twice in 2 years. I’m thinking barn doors to maybe be a good idea for my door replacement this time as they mount outside, which will make it much harder for the wind to bend them. Do you make or can you suggest a door to replace these doors this time that will not get blown out by the wind? Thanks for your time and trouble. JOHN in SOLANO

DEAR JOHN: Sliding ‘barn’ doors are probably not your best design solution as very few of them will withstand high winds. What you actually need (at least my recommendation) are wind rated overhead doors. Whomever provided your doors originally (and replaced them) did you a true injustice. https://www.hansenpolebuildings.com/2014/12/wind-load-rated-garage-doors/

Spray Foam, Second Floor, and Bending Posts

This week the Pole Barn Guru discusses a reader’s concern about “condensation leaks” when using spray foam, advice on costs of attic trusses vs traditional second floor, and how to stop posts from bending when the wind blows.

DEAR POLE BARN GURU: I am building a 40×50 post frame building as my garage. It will have concrete floors and HVAC. I intend on insulating the entire building (walls & ceiling) with closed cell spray foam. I’ve read a lot about people having condensation leaks, so my question is: Should I wrap the walls (and/or ceiling) with Tyvek or spray foam directly to the metal? Second question is should I use plywood on the roof for better structure and to have something to spray foam to? Any advice is appreciated. Thanks. CHRIS in BLOOMFIELD

DEAR CHRIS: Closed cell spray foam is a great product, however it would not be my first choice for your climate zone. For best results, closed cell spray foam should be two inches or thicker to prevent condensation, and applied directly to the roof and wall steel. Hopefully you have a well-sealed vapor barrier beneath your building’s slab. With closed cell spray foam, you may experience condensation on your building’s interior, so do not be surprised should you have to mechanically dehumidify. Unless specified as necessary on your engineer sealed building plans, you should not add plywood or OSB to your roof system, as it will add unexpected dead loads to your building system.

 

DEAR POLE BARN GURU: Hello. We are wanting to build a 2 story pole barn winery. First floor winery and second would be air-bnb type rental. We aren’t sure if we should use attic truss or complete the build with a traditional second floor. Cost is probably biggest concern. Space second as we know attic truss would be less room. Would you do an attic truss or traditional 2nd floor type build and roughly cost difference between the 2? Building size will be roughly 40×60. Thank you for your time. CRAIG in ROCK CREEK

DEAR CRAIG: If cost is your biggest concern, then having rental on ground floor will be least expensive, easiest to climate control, more accessible for your guests and easiest to fire separate from your winery.

If your only option is to have rental above winery, going with a second floor type build is going to give you far less costly investment per square footage of rentable space.

 

DEAR POLE BARN GURU: I built a pole barn for my r/v a couple of years ago. I used 4×4 for my posts with a metal roof and purlins with no siding. The posts are set 3′ into the soil with no concrete. Posts are 10′ out of the ground. When we get a strong wind the posts bend slightly at ground level allowing the structure to flex. Is there a way to add strength to the posts or do I need to replace with a larger size post and should I embed the post in concrete or will it rot? MARK in BRADENTON

DEAR MARK: I am frankly amazed your building is standing! This response is not to be taken as a replacement for an actual engineered structural design and should be verified by an engineer prior to moving forward. You should replace 4×4’s with at least 6×6 (it may require 8×8’s depending upon design wind speed and exposure at your site) #2 Southern Pine columns pressure preservative treated to UC-4B (there will be a treating tag on one end of each). Columns should be at least 40″ in ground and backfilled with pre-mix concrete.

Formula for Calculating Wall Girts

An Excel Formula for Calculating Wall Girts, Post Size and Hole Depth
John Minor and I have been friends for nearly 30 years – since his then father-in-law (and my business partner at the time) convinced me John could sell post frame buildings. Well Rod was correct, John could sell buildings – not only for me (twice), but also for some of the better known names in the post frame industry – Morton, Stockade, Cleary and FBi just to name a few.
John is also a cutting edge innovator and has gone from selling post frame buildings, to manufacturing and providing components to the post frame industry. Current he owns and operates Central Perma-column (https://www.heartlandpermacolumn.com/). John is smarter than the average bear and he has the thirst for knowledge which few non-RDPs (Registered Design Professionals – architects or engineers) in the post frame industry do.
December 13, I received this text message on my phone: “I need your help with something”. Although I did not recognize the number it came from, it turned out to be John.
The conversation went on like this – John, “No worries. I’m trying to find an Excel formula for calculating wall girts, post size and hole depth.”
Me, “You would have to write one and they will be very complex due to the tremendous number of variables involved. I’ve thought about having a Wall Girt calculator on our website for Building Officials to use and the reality is, it is a huge undertaking. For it alone, requires all of the building dimensions including roof slope, is building enclosed or partially enclosed? Which means one has to know if doors are wind rated, and where they are placed. Also makes a difference as to where girts are located on building as wind forces are greater at corners. If girts are barn style on outside of columns, do they span a single bay or multiple bays? Then one has to account for lumber species differences as well as visual vs. machine grading.

Best bet would be to layout all of the parameters and put it out for bid on Upwork. Should specify which versions of Code and NDS you want to cover as well as it must conform to the NFBA design manual. For columns, you are now talking 25-35 pages of calcs.
Fun, eh?”
John, “Damn!”
Those “simple” pole barns one drives by every day are in reality highly complex engineered structures (when properly designed). A full set of calculations for a small two car garage can generate nearly 200 pages of single spaced calculations to prove the adequacy of all structural members and connections, from the footings to the last fastener.
Don’t leave your new post frame building to chance – insist upon having only a building which has been designed specifically for you by a Registered Design Professional, on your site, with your dimensions and your doors!

Building a Pole Building Style Home

Building a Pole Barn Style Home

Reader DAVID from NINE MILE FALLS writes:

“I am building a pole barn style home. I am having a difficult time in finding what the requirements would be for post setting and post distance spacing in regards to a pole barn used for living spaces. I plan on using 8×8 PT posts into the ground.

The question is what would the requirements be as to setting (post foundation) and spacing of posts in respect to a living space?”

Mike the Pole Barn Guru advises:

You have the absolute right idea in considering a post frame building as your new home. Where you may onto a different set of tracks is in trying to work from a certain size or spacing of materials. The best way to get the results you are looking for is to share your ideas of the ideal perfect overall dimensions (width, length, height and roof slope) as well as the look you are trying to achieve with a post frame building kit provider who can design structurally to best meet your needs.

While 8×8 sounds like a big piece of wood, in the Pacific Northwest most of the pressure preservative treated post frame building timbers are one of several species of tree known collectively as Hem-Fir,. In order to adequately accept pressure treating Hem-Fir timbers must be incised, which reduces their strength and often causes the need for larger columns.

Check out more information of incising here: https://www.hansenpolebuildings.com/2014/08/incising/

Other factors which will influence the needed material for columns include climactic loads (wind, snow, rain, seismic), building dimensions (especially height), roofing and siding material choices and soil bearing capacities. Buildings with siding or roofing materials other than steel are typically required to have much more stringent structural specifications when it comes to the allowable deflection of members.

Here is some interesting reading about columns: https://www.hansenpolebuildings.com/2014/06/poles-2/.

Give us a call on 866.200.9657 and any one of our Building Designers can help you design the pole building home to meet structural standards. Best of all, the plans are stamped by a Registered Engineer and come with the many pages of calculations to support your safe home.

 

 

 

Pole Sizes, Adding On a Shed Roof, and Ridge Vents

DEAR POLE BARN GURU: We live in Pacific county in Washington state and wondering what size of truss pole we would be looking at needing for a 60 ft truss. We are in a wind exposure “C” and trusses will be on 12′ centers. The building we are planning will be 60’w x 48’d with 15′ eve height. Any help will be appreciated.

Thank you,CRAIG in RAYMOND

Concrete slab in a pole barnDEAR CRAIG: There are a plethora of factors which will go into determination of what size columns will work for your or anyone else’s new post frame
building. These include (but are not limited to):

Soil bearing capacity
Embedment depth
If columns will be tied into a concrete slab
Spacing of wall girts
Is building fully enclosed, partially enclosed or a roof only
Slope of roof
If building has a ceiling
Roofing material

When you order your new post frame building package, all of these variables will be factored into the design of not only the columns, but all of the components and your building plans as well as the supporting calculations will be sealed by the engineer of record.

 

DEAR POLE BARN GURU: I want to attach a shed roof along the side of my 40 foot pole barn. The span is 12 feet and I plan on the outside of the roof being on 10 ft. high 4×4’s and raising it to a height of 12 ft. on the pole barn. There are 5 6×6’s to line up the 4×4’s to. I was wondering the most cost effective way to attach the metal for the shed roof. I plan on enclosing the sides when funds permit, but for now help with what type of construction, be it wooden trusses or just 2×6 or 2×8 rafters.

Thanks in advance for all your assistance. BEN in TONEY

DEAR BEN: The most cost effective method (as well as structurally correct) will be to discuss your project with a Hansen Pole Buildings’ Designer. With your investment in a new post frame building will come plans which correctly size and locate all members as well as detailing all of the connections.

With this said….

The 4×4 columns you propose using will not be adequate to carry even the most minimal of loads which will be imposed by Code.

Your shed will be designed with a single rafter on each end, and rafters on each side of the interior columns. Depending upon the load conditions at your site, expect to see 2×10 or more probably 2×12 rafters. Purlins on edge will be joist hung between the rafters and the roof steel will attach to the purlins with screws.

DEAR POLE BARN GURU: I paid for continuous roof venting and I got plain 14 in ridge cap can you look in to this? JOE in CLEARWATER

vented-closure-strip

 

DEAR JOE: The steel ridge cap itself does not change for a vented ridge – the foam closure strips beneath the ridge cap provide the ventilation. According to our records, you were shipped the correct vented closures. Please advise if by some chance you did not receive them.


 

 

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