Installing Foundation Insulation in a Pole Barn

[LifeLongWNYer]

Some of you may recall my frequent questions as i design a pole barn, to be used as a automotive/general shop, NONcommercial.

Now I am working on the insulation. I am planning to put down 4 4.5" inches of concrete over the subfloor and laying the concrete plastic pipe for hot water heat. I have read that there should be vertical insulation along the perimeter of the foundation ( as well as between the gravel subfloor and concrete ) but I am wondering how to install it.

The pole barn contractor uses an auger to drill the holes for the poles, and then backfills the hole. When I install the vertical insulation, how do I go about it, without dislodging the backfill around the poles? The bottom of the poles in this area need to be 48" below grade, and that is about the same depth that the insulation goes to. If I dig, or trench, along the walls, for the insulation, won't digging and removing the fill right next to the poles tend to destabilize them?

What is the right way to do this?




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[Bighead38]

Seems like that’s awful deep for the insulation. What’s the reasoning for going so deep?

 

[matt_i]

As Bighead mentioned, your edge-foam just needs to go the depth of the concrete plus a few inches. 8" deep would probably be plenty. Then heat would be trapped by the acre of sub-slab horizontal insulation. If it were my shop I'd use the 25psi version.

 

[Rc_Guy]

Polebarns don't have foundations do they?

 

[OptionalStop]

I'm also in Rochester and building my first pole barn this spring by myself. My plan for the edge insulation is to use the trenching machine I rent for running utilities to dig the slot to put the edge insulation in. Maybe you can use a machine and get real close to the posts with it and get it done quickly. Like others have said, you don't need to go 48" deep with it.

 

[ConCretin]

I'm not a pole barn guy but how about just extending the insulation horizontally a few feet, which would keep frost out from under the structure. You could angle it downward a bit to allow for cover. With in-floor radiant, you'd still want to insulate the slab edge but that's pretty simple.

 

[kj_mustang]

I didn't think you needed to worry about doing deep vertical edge insulation if you insulated under the whole slab, ie: only run it deep if you were not going under the slab with insulation. If it is a floating slab for a pole building, 2" thick foam on the edge and under the whole slab should be fine. I did 3" on the edge and 2" under. My slab comes to the top of my bottom skirt board.

 

[finn]

Do it like KJ shows

 

[renloy]

Sounds like he's talking about only doing the perimeter insulation and not putting it under the floor.

 

[LifeLongWNYer]

Hi folks... I can add some clarification...

I do plan to lay insulation under the concrete, in other words, on top of the gravel subfloor, but under the concrete, and reinforcing steel. I just didn't say that, sorry.

Thanks for the reality check on how deep to extend the horizontal insulation at the foundation. I have an "installation" guide from one of the suppliers of radiant floor heating parts, and I "thought" that it said to run the insulation down to the frost line, which around here is not quite 48". ( My town considers the frost line at 42" ) I'll look at the book tomorrow, when I am at the site where Ill be raising the building and where the paperwork is. Maybe I recalled it incorrectly.

The photo from KJ Mustang was a big help. I was planning, until now, to run the vertical insulation in a straight line on the inside of my poles. It looks as if KJ ran it on the outside of the poles. Which is correct/proper/better? Running it like KJ shows will make for difficult work if doing it like OptionalStop suggests.


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[ricpad]

I used 4" of xps 10" deep around the perimeter, on the floor for the first 2' of the perimeter I used 4" thick xps, the rest of the floor 2" thick xps. The slab was 6" thick. I also fabricated a thermal break across the garage doors that was 2" thick and also went down 10". I am located in NNY.

 

[ToolmanGary]

When I built my pole barn I did things a little different because I wanted a barn with a good foundation.
I dug down 48" with a 18" bucket, then poured 12" of concrete with rebar in it. All my posts are anchored to the 18" spread footing, I dry stacked 3 course of block between the poles and put 2" of foam insulation on the outside of the block. When the floor was poured it filler the block. I went with in floor heat so I put 2" of foam insulation down, vapor barrier, wire mesh, tied the pex tubing to the wire mesh and then poured the floor. I also put some of the foam insulation on the inside of the skirt board like the picture above.

 

[96PSD]

I installed 2" pink foam board 2 feet deep around the whole perimeter of my pole barn except where the garage doors were. I laid 10Mil black plastic as a vapor barrier on top of the 5" of 3/4" clean gravel compacted underneath. Poured a 5" slab with fiber added