Tag Archives: Post size

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 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



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.