Support spacing for pole barn structure

Alesandro · May 10, 2017

Hopefully I can explain this the way I see it in my head. I was wanting to build an aluminum structure to cover 2 campers (1 mine, the other my brothers). I'm pretty sure I want this thing to be 30' wide by 27' deep, lowest part of trusses to be 10' high. I decided to go pole barn style so I can buy material as funds develop and to take my time instead of buying the whole kit at once.

Here's my question, in designing this how far apart should my support spacing be? I'm thinking of using either 6x6 or 8x8 poles 15' long. That way I could bury 4' of the pole then chop the top to make the tops level as needed. I think I seen somewhere where someone had their poles 9' apart, I was think 10' or 12' apart so there would be less cutting as you can buy lumber already in those lengths.

Just looking for some guidelines, thanks for the help.

shadetree · May 10, 2017

Since we are just thinking here: Go to Lowes or HD and see what 8 x 8 x 16 post cost. Putting them 12 feet apart 12 + 12 = 24 + 12 = 36 too long or too short. Trying 10 + 10 = 20 + 10 = 30 closer but still doesn't fit. 9 + 9 = 18 + 9 =27 you did say 27 deep. But like you said a lot of cutting. Check what size the aluminum comes in. I try to think in 4 x 8 sheets but get messed up when joining them on center. I just gave up and bought a good saw.

quicksandfarmer · May 10, 2017

There is no standard answer. Pole barns are designed to be cheap, which means balancing the cost of materials against the cost of labor. The optimal answer depends upon your local conditions, local cost of materials, and local labor cost.

Do you need a permit? If so, will you need approved plans? You can often get those from whoever you get the trusses from. Even if you don't need approved plans, find out from your local or state building department what standards are for snow loading, wind loading, and soil bearing, those will all affect your design. I wouldn't recommend designing it yourself if you haven't done this kind of thing before, get plans. You'll probably be able to find plans with spacing anywhere from six to twelve feet.

RedNeckRacin · May 10, 2017

ive seen spacing from 8' to 10' mostly. I would echo the comment about thinking in 4x8 sheets to make your wall coverings work out. I think that tri-rib comes in an odd size like 39" sothat doesnt help. If you do 8' spacing all the math gets much simpler for quantity take-offs. Definitely look into the building permit and pole barn plans are pretty cheap.

Oldoak · May 10, 2017

My 48' w x 30' d pole building 6x6s are spaced 12' apart on the width and 10' apart on the depth. The addition 14' w x 30 d the post are 14' apart on the width of the addition to allow for plenty of clearance for our travel trailer.

The distance you space your posts depends a lot on the what is used for the header.

I hope all the new rules and regulations for simple pole building haven't caught up to your area yet like they have ours. Among other new building codes, the "authorities" have mandated no wooden posts (even if treated) can be direct buried in the ground. They specify how deep and what diameter the holes must be and then filled with concrete up to ground level and then the wooden posts are anchored above ground.

Our 40+ year old pole building with the posts buried in the ground is still standing.

I would suggest going at least 30' in depth with your new building. Material wise, it will work out a lot better and you will appreciate the extra footage. Good luck with your new building.

quicksandfarmer · May 10, 2017

I like to poke around on the Armour Metals website, Armour Metals - Metal Roofing and Pole Barns . I can't in any way recommend their product, good or bad, but they have a lot of interesting stuff. They have a polebarn estimator that lets you put in the dimensions and it produces a complete list of materials. (Although they don't say anything about loading for wind or snow, their designs seem flimsy to me.) Plus lots of pictures and videos of barn construction, and prices on the website for comparison.

cat fever · May 10, 2017

I think if you just changed your size to 30' X 30' and spaced your 6" X 6" post 10' apart it would would out great. The metal comes in 36" wide and heavier gauge comes in 39" wide. Here is some pictures of a barn I built two years ago. My post are 12' apart, but I'm 72' long. I think it's similar to what you are wanting to build.