Pole barn on plate?

[MacLawn]

Whew, I thought I knew something! I don't know nary a thing! But, I'm full of questions. I'm planning to build about 36'x36' (maybe 36'x40') this summer, pole barn or post/beam type. Okay, I am planning to dig holes about 8' on center (will change this as necessary, maybe 6' or 10' on center), 3' deep by about 8" square form and pour concrete in the forms up to where all of them are level. Can y'all picture what I'm talking about? It'll be a heap of concrete square "posts" sticking up all level at least 8" above ground level at the lowest point. I'll insert those galvanized post attaching thingamabobs while concrete is still soft and attach me 6x6 ground contact treated posts to them when cured. Then I'll run treated boards around the bottom of posts, notch out for headers at top (10' at eaves) and put up me trusses. I'll put plenty of boards laterally around the barn to later attach siding when I can afford siding.

I'm in Georgia, so hard clay dirt, but don't want me posts in ground. I'll do work meself with helper. So, Eddie, what ye think about me plan? I know you're a builder, so I trust your advice.

 

[EddieWalker]

I like posts in the ground because of the amount of strength they give you, but if you want to create footings for each post, that's a proven building technique that works too. Just more work and money. I don't think I would go ten feet on you spacing for the simple reason that I like my purlins to be on three posts. At ten feet, you need to have 20 foot purlins, which isn't that big of a deal, but it gets expensive knowing that a 2x6 will sag or bend on you at ten feet. At 8 foot centers, 2x6 purlins 16 feet long should never give you any problems. You can also put your trusses right on top of your posts and have them 8 feet apart with 2x6 purlins on edge for your roof.

Eddie

 

[KennyG]

Regarding modern stick built residential construction on top of a concrete slab...

My wife used to work for a large residential builder in the Dallas area. One of their "better than the other guy" selling points was that they not only nailed the base plate down, but they also put anchor bolts down through the base plate every four feet. Said it was tornado proof.

I just laughed when I heard that. Okay, maybe the base plate is tornado proof. But all the vertical studs are still only nailed down to that base plate. If a tornado hits your house, you're going to be left with a slab and a base plate instead of just a slab.

xtn

Like most things, this works if you actually follow code requirements. In most places, the bottom plate is required to be bolted. The old concrete nail approach doesn't meet modern code. As someone noted above, the sheathing needs to be lapped onto the bolted bottom plate. That gives you tremendous shear capability in addition to the studs nailed to the plate. A properly built house can be destroyed by a tornado but it will not be lifted off the foundation. The walls will be ripped apart. The weakest connection becomes the roof to the walls which is why the tornado/hurricane straps are required in most locations.

 

[Woody65]

Whew, I thought I knew something! I don't know nary a thing! But, I'm full of questions. I'm planning to build about 36'x36' (maybe 36'x40') this summer, pole barn or post/beam type. Okay, I am planning to dig holes about 8' on center (will change this as necessary, maybe 6' or 10' on center), 3' deep by about 8" square form and pour concrete in the forms up to where all of them are level. Can y'all picture what I'm talking about? It'll be a heap of concrete square "posts" sticking up all level at least 8" above ground level at the lowest point. I'll insert those galvanized post attaching thingamabobs while concrete is still soft and attach me 6x6 ground contact treated posts to them when cured. Then I'll run treated boards around the bottom of posts, notch out for headers at top (10' at eaves) and put up me trusses. I'll put plenty of boards laterally around the barn to later attach siding when I can afford siding.

I'm in Georgia, so hard clay dirt, but don't want me posts in ground. I'll do work meself with helper. So, Eddie, what ye think about me plan? I know you're a builder, so I trust your advice.

Maclawn, Eddie must be busy so I will try and answer some of your questions.

The 8' on center spacing for the poles is the norm in pole construction, so you should be fine with that. The depth of the pier foundation that you describe depends on your frost line. Since you are in Georgia, 3' should be plenty deep. I would use 12" sonotubes for the footings to put your posts on. The weak point will be your connection between the poles and the concrete pier footings. Pole constructions gets its shear strength from the poles being in the ground a minimum of 4'. This keeps the structure from tilting side to side from different climate conditions. In your case, I would purchase a high quality connector that goes up the post at least 3' and into the cement with a 12" J hook. The rest of your ideas are in line with common pole barn construction re: treated bottom board, headers, girts and purlins usually are applied 24" on center to attach metal roofing and siding. Hope this helps some. And, I am a builder also.

Didn't see Eddie's response till after I posted.

 

[EddieWalker]

Just a note on the bolting the sill plate to the slab. I have a SDS and an SDS Max drill for concrete. Both are great for sill plates. I put the plate down, drill a hole through the plate with a standard drill bit, then drill down with my SDS Max. It's just melts through concrete and makes it very easy to attach anchor bolts. I never use nails in concrete to anchor anything. It's just too easy to drill the holes.

The bolts are just the first step to anchor the building to the foundation. You also need metal strapping that is tied to the rebar in your footings and goes up the studs. In CA, where I'm from, they where requiring the straps to start in the footing and go up the wall and tie into the rafters. They had to be continuous. I'm not saying this will withstand a tornado or hurricane, but depending on how hard you are hit, it might.

Eddie

 

[MacLawn]

Eddie and Woody, well, y'all boys just come on over (for Eddie) and down (for Woody) and let's knock this thing on out! :cool2: I ain't afraid of work either - I can sit around and watch it all day...:laughing:

Really, y'all have helped me a heap! Will my idea of wrapping the bottom of the poles where they tie into the piers with 2x6 or 2x8-10 treated boards be strong enough? I will use those LONG J bar thingamajigs in the concrete and up the posts. And posts will be 6 or 8' on center now. Using the top board to tie trusses onto sounds good.

Or, I might just throw my idea of concrete piers out and put posts 4' in ground, although I really want to avoid that. I'll post pics this summer when I get started. Thanks boys (me Southern lips have a hard time saying you guys).