Insulation on foundation

[Horses Ghost]

They are about to pour the floor in my 30X60 garage in the morning and the question I have is they put 2" foam on the inside of the footings. It now has 2" foam on the base with pex, 1" of sand, wire mesh and rebar. The question I have is they left about 6" of foam sticking out to the top of the foundation. I thought that it would be cut out before they pour the slab. Please advise. Thanks...Mark

 

[Horses Ghost]

Anybody have any advice?

 

[GearBeer]

Mark,

I would guess that it needs to be cut back. Is it between the pad proper and the "shelf" where the pad will sit on the foundation?

 

[GSSFC]

They did that on mine. It was a mistake and has caused lots of problems. It should have cut back!

Tim

 

[egads74]

If I understand this correctly, your saying the foam is on the inside of the foundation and across the floor (to be under concrete) is 2" foam. So the poured floor will never touch the outside foundation. Isn't this correct? Otherwise without it, heating the floor would have a major loss to the outside foundation. Right?

 

[GearBeer]

You're going to have to have contact between the floor and the foundation for structure. The pad will be VERY prone to cracking without it.

I would cut the foam down to the level of the foundation and add 1" foam along the sides of the block/poured "wall" to mimimize the heat transfer. The foam along the wall should be below the level of the concrete so the concrete will cover it and it can be easily sealed so your first gas spill doesn't destroy your insulation. The insulation against the wall will also function as an expansion joint.

 

[GearBeer]

Just to be clear, this is what I mean: