In Floor heating insulation question

[JBAUTO]

Quick question guys. When doing the exterior of the slab how far down do you do your insulation ??

I was going to 2" foam 1" down against the footing wall like this in the pic? Or should i got 2 feet down the wall. Here is a pic.

Oh the top is going to be cut at a 45 deg btw

 

[JBAUTO]

I think what im going to do is vapour barrier the wall down 20-24" then put a piece of 16" high 1" thick piece of insulation around the whole footing wall. Then back will it once its all graded and level. i will vapour barrier the flor and go up the wall then place a piece 4" high 1" thick around the whole wall against the 16" piece on the wall being seperated by the vapour barrier then the whole floor will be 2" foam.

Will this work ? If needed i can draw a picture.

So it will be footing wall, vapour barrier,16" piece of 1" thick foam, vapour barrier, 4" high of 1" thick piece of foam.

 

[bimmer1980]

I had plenty of foam, so I went all the way to the top of the footing. about 4'.

 

[Ezzie]

No need for a vapour barrier if you are using closed cell foam - just tape the seams with Tuck Tape if you are concerned about it. In our area (Ontario) we should be fine with the foam down 2' from the top of the slab on the inside of the foundation wall. If you do it on the outside of the foundation wall, you need to cover it with something for the above grade portion of the wall to prevent damage.

In my case, the contractor actually placed 1.5" foam inside the foundation wall (think sandwich with the concrete as the bread and the foam as the meat).

 

[JBAUTO]

Ok perfect. Reason i was asking was cause i was getting 10 different answers. We are doing a building at work 60x60 and they used 2" foam 2' feet down the wall with no 45 deg cut they just moved the foam down 4" and put this 1/2" like cardboard stuff around the whole inside of the perimiter/.

 

[rlme36]

Ok perfect. Reason i was asking was cause i was getting 10 different answers. We are doing a building at work 60x60 and they used 2" foam 2' feet down the wall with no 45 deg cut they just moved the foam down 4" and put this 1/2" like cardboard stuff around the whole inside of the perimiter/.

I used 2" foam on the entire perimeter of the walls approx 2 ft down, then used 1" foam as on top as the spacer between the slab and the wall if that makes sense, then cut the 1" or so of foam sticking above the slab down to the slab height.


rob

 

[JBAUTO]

One more question

where the slab goes out for the garage doors. What do you do to isolate the slab tithe footing wall as it goes over it?? I was going to put a piece of 1/2" foam over the top of the blocks so the slab will not transfer heat to footing wall???

 

[jklingel]

When you look at isotherms of the heat leaving the slab, they go down several feet. Going down four feet is not unreasonable at all. Also, the thicker the better. GL. j