Barn project - setting concrete piers

[dustinfox]

I'm working through plans to erect a barn and there is something I haven't been able to "get a handle" on. I'm thinking of setting PT 6x6 posts on concrete piers as footings. How can I set the concrete piers or forms in place and be sure that the PT posts will all sit in perfect position, such that they will all be plum and aligned? I know how to "square up" a footing and align the holes for the piers, but it seems nearly impossible that you could fill tubes with wet concrete, insert post brackets, and have everything so precisely aligned that all of the columns would be perfectly plum when finished. If I set concrete piers like this for a large barn (say 28 x 40? with metal receptacles for the wood posts embedded in the concrete, I cannot image achieving the kind of precision needed to avoid having to tap the columns into plum.

Am I missing something here?

Thanks!

 

[MarkV]

Normally you would do it with batter boards and string. If you square up your strings, remove to drill your holes and then reset the strings to set the brackets you should be there.

There are differing opinions but...having the poles in the ground contributes greatly to the racking resistance and up lift resistance of a true pole barn. If you are planning on tin siding keep in mind it really offers little to make a building ridged where with a house the ply sheathing forms a ridged unit to resist movement. Poles on brackets are a hinge point for movement so be sure to include a lot of diagonal bracing.

MarkV

 

[dustinfox]

Normally you would do it with batter boards and string. If you square up your strings, remove to drill your holes and then reset the strings to set the brackets you should be there.

There are differing opinions but...having the poles in the ground contributes greatly to the racking resistance and up lift resistance of a true pole barn. If you are planning on tin siding keep in mind it really offers little to make a building ridged where with a house the ply sheathing forms a ridged unit to resist movement. Poles on brackets are a hinge point for movement so be sure to include a lot of diagonal bracing.

MarkV

Yes I agree... I'm leaning toward PT posts with no concrete piers. Just a little concerned with how long they will last. Also I like the wide bottom on the concrete forms to resist sinking. I suppose I could pour footings for the posts but I've heard arguments against that too.

 

[MarkV]

It is pretty standard, actually code here, to set posts 4' deep setting on a 16"x6" round footing at the bottom of the hole. Most barn building companies use store bought footing of those dimensions so they don't have to wait for the concrete to dry. As far as the poles rotting I consider that a problem with site prep. If your barn pad and roof runoff are such that water can't get to the poles you will be good. There are a lot of pole barns around me that are older than I am and I am in my 60's.

MarkV

 

[dustinfox]

It is pretty standard, actually code here, to set posts 4' deep setting on a 16"x6" round footing at the bottom of the hole. Most barn building companies use store bought footing of those dimensions so they don't have to wait for the concrete to dry. As far as the poles rotting I consider that a problem with site prep. If your barn pad and roof runoff are such that water can't get to the poles you will be good. There are a lot of pole barns around me that are older than I am and I am in my 60's.

MarkV

Thanks! Good tip!

 

[MotorSeven]

Marks right, put a string on everything. They make 6x6 brackets that have a leg that goes into the wet concrete:
6x6 Elevated Post Base-EPB66 at The Home Depot

There are many variations and prices, so shop around. Once up each post will need to be braced to the ground at 3 points. Get the two end poles straight and level, put a string on them, then bring the others up in line with that string. Once all posts are up, check for square, them make adjustments if needed.

I don't know about the wind thing. Here barns 75-100 years old are still standing. They were constructed using 4-8"poles set on slabs of limestone...that's it. I think it takes a really really big wind to blow one over so I am not sure it the tin roof would survive a wind like that anyway. Most here that have failed, lost some roof at one time or another, no one fixed it, water rotted the structure on the inside...then collapse.

 

[dustinfox]

Marks right, put a string on everything. They make 6x6 brackets that have a leg that goes into the wet concrete:
6x6 Elevated Post Base-EPB66 at The Home Depot

There are many variations and prices, so shop around. Once up each post will need to be braced to the ground at 3 points. Get the two end poles straight and level, put a string on them, then bring the others up in line with that string. Once all posts are up, check for square, them make adjustments if needed.

I don't know about the wind thing. Here barns 75-100 years old are still standing. They were constructed using 4-8"poles set on slabs of limestone...that's it. I think it takes a really really big wind to blow one over so I am not sure it the tin roof would survive a wind like that anyway. Most here that have failed, lost some roof at one time or another, no one fixed it, water rotted the structure on the inside...then collapse.

Ya I guess I can see how this would get pretty precise... running string across the center of all your tubes, maybe a black "tic mark" on the string marking the lateral position of each post, and planting the brackets under the mark.

 

[nickel plate]

dustinfox,
You say that you know how to square up footings and such so put that good knowledge to use so take your time and pour the four corner piers first using batter boards with strings set at the hold down's top elevation or higher and offset as MarkV suggested. After they have set up, run your string from the four corner hold downs and finish the rest of them in between. That should give you peace of mind and make the job right from the start.
As far as the metal hold down embedments go, use the heaviest gauge you can find and check the catalog as you can most likely special order them in with a better surface coating for exterior usage. You might want to get those rolling your way pretty soon as they may take a few days to acquire. Any good local lumber yard can set you up with them. Look into both the through bolt version and the engineered milti wood screwed type. There should be an 800 tech support phone number in the catalog. Try Simpson Strong-Tie Corporation.
Good luck and post photos.

 

[dustinfox]

dustinfox,
You say that you know how to square up footings and such so put that good knowledge to use so take your time and pour the four corner piers first using batter boards with strings set at the hold down's top elevation or higher and offset as MarkV suggested. After they have set up, run your string from the four corner hold downs and finish the rest of them in between. That should give you peace of mind and make the job right from the start. Good luck and post photos.

Thanks, I will post pics. I guess with some diligence, planning, and helpfull tips from the folks here, it certainly is possible to get that kind of precision!

Thanks again! :thumbsup:

 

[dustinfox]

I am also "toying with" the idea of using laminated posts (i.e. using three or four 2x6s to sandwich together my posts. Any thoughts on that? It would make construction more managable for someone working alone.