Pole barn-- newbie-- need advice

[southga]

South Georgia. 24x40. Soil is primarily sand. Dirt floor. It is crowned away from center in all directions.

Would like to have no center posts if possible.

Plan is to drill holes 42 inches deep, 6 inches of gravel, concrete the poles.

Use 6x6 PT posts. 10 feet apart.

So 10 posts total, 5 on each 40 foot side.

2 2x4s for top plate.

premade trusses.

tin roof.

thoughts?

questions:

how do you support the posts while the concrete sets? I know I'll use 2x4s but how many and how tall for each post? How do you keep them firm on the ground? Use screws to secure them to the posts?

Can I then use these same 2x4s for the top plate?

should the concrete be at ground level?

Any help is appreciated.

 

[southga]

Oh I forgot...

10 foot clearance to top plate.

 

[Kyle241]

Just a question concerning your top plate. Only 2"x4"? I am building a pole garage, 24x32 and my top plates are 2"x10" that will 'sandwich' the posts secured with galvanized 10" lag bolts and a 2' section of 2"x6" vertically on the post each side. Now up here, we have snow loads to contend with but I think 2x4's are a little light. I would definitely go with at least 2x6's minimum.

 

[DaveOmak]

For what it is worth, some say concreteing in posts holds moisture and will rot your posts faster than packing crushed stone around them. The poles can be adjusted while packing the gravel around them. Putting a 12" concrete "punch pad" in the bottom of the post hole will stop the posts from sinking.
I paint my posts with a mix of diesel fuel and diesel crankcase oil even if they are treated.
Don't know if any of this works because I haven't pulled the posts to do a study.

 

[whistlepig]

South Georgia. 24x40. Soil is primarily sand. Dirt floor. It is crowned away from center in all directions.

Would like to have no center posts if possible.

Plan is to drill holes 42 inches deep, 6 inches of gravel, concrete the poles.

Use 6x6 PT posts. 10 feet apart.

So 10 posts total, 5 on each 40 foot side.

2 2x4s for top plate.

premade trusses.

tin roof.

thoughts?

questions:

how do you support the posts while the concrete sets? I know I'll use 2x4s but how many and how tall for each post? How do you keep them firm on the ground? Use screws to secure them to the posts?

Can I then use these same 2x4s for the top plate?

should the concrete be at ground level?

Any help is appreciated.

I have had two barns built by barn builders. The last one is 24'x40'. There are (6) 6"x6" posts on each side 8' apart. There are two 6"x6" posts on each end for the barn door openings. They dug the post holes 48" deep and poured a 12" concrete pad at the bottom of each hole for the posts to sit on. Then the corner posts were set in and loosely packed with a little dirt. Just enough to keep them from tilting. The most time consuming part was getting the corner posts square. They tack nailed stringers and kept tweaking the corner poles until perfectly square. Once the corner posts were square they nailed the outside stringers (2"x6"). Then the rest of the posts were squared and leveled to the corner posts and the outside stingers nailed on permanently. Post holes then filled with dirt and tamped. The top plates are 2"x6". One on the outside of the posts and one on the inside of the posts. This is what the trusses rest on. The bottom of the barn is built slightly above ground level. Too high can be easily filled. Too low means digging. Digging inside a barn is bad. The top of the bottom stringer should be level with the bottom of your doors. Pour the concrete to the top of the bottom stringer. Allow enough on the bottom stringer for the thickness of your gravel and concrete.

 

[Birdhunter1]

The way I did the posts on mine was to notch out the side of them, so that underneath the truss is a 6x6 and the truss sits on top of this and against it is more or less a 4x6. You could also do the same with 3 2x6's (which I also did on mine and I had one 2x6 10' long and the other two I left at 11' and cut them flush with the top chord of the truss.

All of my posts sit on top of a concrete wall though and nothing is in the ground. The top plated on mine are 2x6's but the only thing they hold are the metal on the side and the posts from walking around (but since there are 5 boards up the side of the building I don't see them shifting anyway. I went 8' truss spacing due to our snow loads, I am guessing in your area 10 would work, 10' here would be the farthest I would want to set them.

 

[FrogLick]

I'd say that 2x4 for top plates on posts 10' apart is definitely inadequate. Personally I'd use 2 2x8 at a minimum. Those top plates will be bearing the weight of any trusses not directly over the posts as well as the additional weight of bracing and roofing. I'd also agree that you wouldn't regret going 12' high on the side walls; consider an overhang of 12" to help keep water away from the sidewalls and provide a little shade in hot GA Summers. When I built I used the bottom stringers as my form for the concrete floor and definitely above surrounding grade to keep any water from entering the barn. Poured an approach at the door entrance leaving a lip behind the door to reduce blown rain while still not having to drive over a thick slab edge.

 

[southga]

Thanks for the feedback. Pole barn basically done. Followed advice and upped the top plate to 2 2x8s. Notched poles and set top plate in notch. Went up well.