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.

 

[dustinfox]

I found a couple of helpful web sites for pole building construction. Probably nothing new to many of you guys but it's good information for a novice like myself.

http://www.midwestmanufacturing.com/MidwestManufacturing/web/docs/pdf/PostframeHH.pdf

How to Build A Pole Barn by APB Pole Barns

 

[flusher]

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!

I use this method to lay out foundation posts



Just need 2x4s, a 25 ft steel tape and a 4-ft spirit level along with a bunch of flat steel stakes.

Good luck

 

[dustinfox]

I use this method to lay out foundation posts

View attachment 265044View attachment 265045View attachment 265046

Just need 2x4s, a 25 ft steel tape and a 4-ft spirit level along with a bunch of flat steel stakes.

Good luck

Thanks flusher!

 

[flusher]

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.

I used a combination of glulam/nailam for the beams on my equipment shed--two 2x12 x 16 ft long glued with exterior grade wood glue and pattern nailed.

I've also make redwood posts for the gate to my Japanese garden using the glulam approach

 

[capnbo]

I just started a pole barn that is engineered for
140 winds on the Gulf Coast. In the plans, I had to suspend all 15 posts 8-10" from the bottom of 43" deep holes, 18-24" diameter. I uses 2x4's x 6'temp nailed 32" from bottom of posts. When plumbed and braced, the concrete flowed under the bottom of posts for a good footing. Poured each hole 2/3 with 2500 psi concrete then packed native soil to grade level. After it set, knocked the 2x4's off the posts. This worked great for my plans.

 

[EddieWalker]

I've replaced more porch posts then fence posts. Rot always happens at ground level. With porch posts, it's so much easier for moisture to get up into the post through the end grain and rot the wood long before you even know it's happening. With fence posts, it happens from standing water at the base of the post.

If you make sure that no water is ever at the base of the post, you will never have any problems. The reason some pole barns last forever and others have issues is because of drainage.

By pouring concrete and attaching your posts to the top of the concrete, you are losing all that strength that the post would have given your building by being in the ground. You are spending more money and you are taking more time to do it this way. Unless there is another reason that outweighs all the benifits of setting posts into the ground, I would never build a barn by setting the posts on concrete piers.

Eddie

 

[dustinfox]

I've replaced more porch posts then fence posts. Rot always happens at ground level. With porch posts, it's so much easier for moisture to get up into the post through the end grain and rot the wood long before you even know it's happening. With fence posts, it happens from standing water at the base of the post.

If you make sure that no water is ever at the base of the post, you will never have any problems. The reason some pole barns last forever and others have issues is because of drainage.

By pouring concrete and attaching your posts to the top of the concrete, you are losing all that strength that the post would have given your building by being in the ground. You are spending more money and you are taking more time to do it this way. Unless there is another reason that outweighs all the benifits of setting posts into the ground, I would never build a barn by setting the posts on concrete piers.

Eddie

After lots of research, I have come to that same conclusion. I'm going to set my posts directly into the ground. My initial question is still relevant though, and I can see now how the posts can be set precisely in line so that everything comes out plum and square. The drainage issue is probably the best advice I have seen regarding wood piers. I plan to backfill the holes with crushed stone or gravel and landscape so that water will run away from the posts and not collect at the base. I'm still not clear though on whether a concrete footing is appropriate. My thinking is that perhaps I would be better off with six or eight inches of large stone (maybe 1 1/2") at the bottom of the hole. This would allow moisture to percolate down and away from the end grain of the posts.

 

[MarkV]

Most pole barn building companies use 16" concrete donuts at the bottom of the hole as a footing. In my area it is code. You may not be subject to code but to me there is no reason to out guess the engineers at the pole barn companies.

MarkV

 

[Darrenone]

I am in the process of building my pole barn right now and set all my 6"x 6" in the ground. I actually threw a bag of concrete in the hole and set the post on top of it just to get a bigger base. All the pole barns around here that I know of just set the posts in the ground and there are some old barns around that are still solid as can be. I have build many decks over the last 25 years all with post set directly in the ground and have never heard of any that the post have rotted. Slope the grade away from the building and all should be fine. Good luck on the project!

Darren

 

[s219]

After lots of research, I have come to that same conclusion. I'm going to set my posts directly into the ground. My initial question is still relevant though, and I can see now how the posts can be set precisely in line so that everything comes out plum and square.

Around here, for decks, we nail the structure together and prop it up with all the posts hanging in their holes. So you use the actual squared-up frame to position the posts where they need to be, rather than doing in the other way around. Once it's ready, we pour concrete into the post holes so that it flows around and under the posts.

I plan to use the same procedure for my pole barn with some modifications. First, I will dig all the holes, and line the bottoms with some gravel and a small concrete pad for the post to sit on. Then all the posts will be put loose into the holes. One wall at a time, I will run purloins across the posts to square them up and form the basic wall frame. I'll join two walls at a corner, and do whatever jiggling needed to square up the corner and brace it with the posts roughly centered in the holes. Then do the opposite corner, and finally join the two remaining corners. Once everything is where I want it, I will fill the post holes (most likely with gravel, but concrete could be used as well).

With this approach, I plan to leave slop at the tops of the posts (so that all holes don't have to be perfectly leveled with each other) and then once the walls are framed and posts set, just lop off whatever extra post is left at the top.