Pole barn build, questions about concrete

[cghbuilder86]

I am planning to build a pole barn for tractors and farm tool storage and insulated wood shop. I originally planned to build an open pole barn for my farm storage and a separate building on concrete piers with a wood floor foundation. Then decided if I could combine the two it would be cheaper mainly in using an existing concrete for the floor of the wood shop and not doing a wood floor. I have an old rotten falling in barn over a big rough poured concrete slab. I want to tear the old barn down and use the concrete slab. It looks on one side like it may be 3-4" thick and on the other side its level with the ground. So I don't know if it tapers down thin on that side or if the ground is just filled in so its up level. Anyway, the concrete is not at all level and pretty rough so building walls on the edge is not really an option. The edges in some areas are not straight and break away in some spots. Its about 22 feet wide and probably 70' feet long. Longer than I need it to be. So I was thinking of doing 6x6 treated edge poles in the the ground about 24' wide and one row of poles in the center. I'll build it with no wall in the front across the width leaving it open for backing in tractor, horse trailer and some equipment. Then a wall behind all that starting into the woodshop area. I want the wood shop to have insulated walls and will probably put a ceiling and small attic area with insulation so I dont have to insulate in the roof rafters. Now for the question. I want to make sure I dont have any water running in along the base of the walls and need to make sure the wood walls and insulation don't soak up any water. Can I just screw two 2x6's against the poles one on the inside and one on the outside of the poles against the ground to pour a small 6" tall concrete wall between the poles and then place a treated 2x6 on top of it to be my bottom wall plate and then frame up 2x6 walls between the poles? It seems that way my walls and insulation would be off the ground and have somewhat of a seal against the ground. after pouring the short concrete wall I would just remove the 2x6 form boards against the sides of the poles and pour a little concrete on the ground to bridge the gap between my old rough edge slab and my concrete short wall between the posts. I know that concrete breathes and would allow some humidity to move in and out. And I don't think that would be a problem. It's not a house or anything. I just don't want any water to be able to seep in or have my walls right on the ground where the wood could deteriorate or cause my insulate to be damp. By the way there is decent water run off away from the building. I wouldn't have standing water on the outside of the concrete wall or anything that would be likely to let water in if it ever cracks a little or anything. So will this plan work? Will the wall stay good and dry? And what kind of prep on the ground would be needed to pour this wall between the posts and on the ground connecting to my slab? Just removing grass and debris smooth out the dirt, level it some and pack it down? any info would be greatly appreciated!

 

[matt_i]

My opinion is yes, you can build a short wall next to an existing slab to elevate your framing. However somehow it needs to be anchored below the frost line or its going to heave itself into a broken mess over time. Not sure if your thickness is enough to edge-dowel with rebar, it helps keep alignment but won't resist the freeze heave.

Along the lines of keeping water out, the three best things you can do are: keep grade below finished floor, slope grading away, as significantly as possible, and use gutters on the sidewalls to route water predictably and avoid the "drip trench" and its resulting splash up on the sidewalls of the building.

I'm curious if you have driven the tractors over the slab already? This is a pretty good litmus test as to whether it will hold up or if simply too thin. The size of the tractors matters too, a 14,000 lb 120hp turbo diesel is different from an 8N.

 

[cghbuilder86]

Yeah Maybe I'll get some info on here with the best way to handle the frost line. I will say that I live in Mississippi, I think according to the frost line maps I have have a frost line of about 5-6" deep. Yeah, I keep my tractor in the old mess of a barn there now. It has never affected the concrete any. It is just an old Ford 601. I just keep it around for small jobs. I won't ever own a giant massive tractor. If I ever upgrade it will most likely be to a newer lighter weight model with a stronger diesel engine.

 

[cghbuilder86]

Nobody else has any input on this? In Mississippi we have a shallow frost line of like 5". Should I make sure the concrete wall I pour is dug down below this?

 

[Leaflessshadetree]

Nobody else has any input on this? In Mississippi we have a shallow frost line of like 5". Should I make sure the concrete wall I pour is dug down below this?

Yes, and have a footer (wide base) under it. I'd go deep enough to keep animals from burrowing under it.

I'd also span the 24 ft with trusses rather than having poles in the center, 12ft isn't very wide.

 

[DougWil]

Nobody else has any input on this?

Yeah, that monster paragraph sure is hard to read.

I think I would sawcut the slab straight, dig a footing, pour a footing and a build up a cmu wall as high as you want to go.
From there up wood framing bolted to the top course of the cmu.
Let the slab float.

Waterproof the exterior of the cmu with asphalt coating all the way down the face of the footing.

Putting wood poles in the ground not only rot but provide a gap in your concrete stemwall for water and bugs to get in.

If you want your shop framed for an attic, ceiling, insulated, sheeted, wired etc,,, a pole barn saves little to nothing over stick frame, with a much shorter life.

 

[cghbuilder86]

Good responses, give me a lot to think about. Thanks for posting!