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!

I want the Bottom of my Poles at the Same Depth

I Want The Bottom of My Poles At The Same Depth

“Dear Pole Barn Guru,

I am putting up a 24’x32’x10′ pole barn to serve as a garage. Last weekend I augered my 24″ holes to accommodate 48″ post embedment plus a 10″ concrete footer. A ready-mix company is coming on Friday to pour the footers.

Last night I ran my laser level and saw that the depth of the holes varies within a ~6″ range. My question is, it is acceptable to place compacted gravel (304 limestone or similar) 4-6″ at the bottom of the “deeper” holes to bring them up to the same level as the “shallow” holes?

My concern is that some holes will end up with gravel and others won’t. I’d prefer not to manually dig out the “shallow” holes, and don’t want to spend the extra money on concrete as a filler.

Cheers!”

Mike the Pole Barn Guru Writes:

In the global scope of life, the uniformity of the depth of your columns will not make a difference structurally. You will be cutting off the tops of the posts in any event, so no one except you, me and 100,000 (give or take) readers will know!

I would not suggest placing gravel at the bottom of any of the holes, as it is going to be virtually impossible for you to adequately compact it – leaving the possibility of settling a force to be reckoned with.

Here are some options…..

If your holes are actually 58 inches in depth (48″ of post embedment plus 10″ of footing) and you have ordered 16 foot long columns, you do not have to do anything. If the columns are 14 feet long, then you can suspend (float) the columns so the base ends up at 48 inches deep, by nailing a board across the column so as to support it on each side of the hole. Then place the column in the hole and mono pour both the footing as well as the concrete bottom collar to prevent uplift.

If your building’s engineer did not specify the use of a bottom collar then this is the time to be able to resolve this oversight and do the job right.

If the 10″ of footing is included in your 48″, then (regardless of whether you ordered 14′ or 16′ columns) you can again suspend the columns and mono pour the footing and collar together.

You are also talking about a very small quantity of concrete here – 12 footings two feet in diameter by 10 inches thick only takes just over a yard of premix. You might as well order enough concrete to avoid the typical \$100 short haul charge (usually takes 3-4 yards) and pour the concrete in around the columns to provide footings and the collars – giving you a solid foundation which you can trust.

Dear Pole Barn Guru: I Have a Roof Mold Problem

ADDED BLOG DAY!  Due to a large volume of questions to the Pole
Barn Guru, we are adding another day for answering questions – so look for more Pole Barn wisdom from The guru on Saturdays – starting – today!

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: Have a 45′ wide x 120′ long by 20′ tall pole building.  All walls are insulated and covered with plywood sheathing.  Bottom cord of all trusses also sheathed with 1/2″ plywood.  Metal roofing is installed over felt paper that is installed over 1/2″ plywood roof sheathing.  Building has continuous ridge vent and multiple 10″x20″ soffit vents.  None the less we still have mold growing on the bottom side of the roof plywood. Here in Oregon we get ALOT of rain, so frequent moisture issues.  Should I add gable end fans?  Roof fans?  Thoughts. RAINING IN EUGENE

DEAR RAINING: Provided the underside of the ceiling plywood does not also have mold growth, then the moisture is an issue from the enclosed attic space. By Code, the requirement for attic ventilation is for 1/150th of the area of the attic to be in vents, provided at least 50% is in the upper ½ of the attic and at least three feet above the eave vents. This net free area is to be equally divided between the eave and the ridge.

In your case, the minimum requirement would be 18 square feet at both the eave and the ridge. My guess is your ridge is inadequately ventilated, thus the mold issue.

You should begin by replacing your current ridge with a product such as the Klauer Roofline Ridgolator 4 (www.https://klauer.com/metalcomponents.html). With 220 net square inches of free air per ten foot section – your 120 foot long ridge would provide just over the bare minimum required for proper exhaust.

Powered exhaust fans in each gable would certainly help, provided they are located towards the peaks of the gables, and have sufficient capacity to be able to pull air from 65 feet away.

DEAR POLE BARN GURU: What is the depth i should place my poles in the ground in concrete 24×48 10 feet tall not in city. SOMEWHERE IN SNOHOMISH

DEAR SOMEWHERE: As the county you are building in requires Building Permits for all structures the size of yours, and they do a structural plan check prior to issuing permits – you will need to go by whatever is on the approved plans.

Not knowing your design wind speed and exposure, dead loads on the building, roof slope and soil bearing properties, I can only say typically I would expect holes 40 inches deep, with the bottom 18” backfilled with premix. In the event you are constructing a “pavilion” style (all walls open), then it would be best to entirely backfill the holes with