slab insulation for radiant heat?

[LS1NOVA]

Im wondering if I should put the vertical insulation 4ft down to the frost line or if 2ft is sufficient? Also, should I put anything in between the insulation and outside ground?

Im in the Minneapolis MN area.

Thanks

 

[LS1NOVA]

Anyone? Im starting the excavation for the slab today.

 

[leeklm]

check out Radiantec online. Good website, lots of info. I purchased a system from them couple of months back. Pex, manifolds, pump, shipping, etc. came to $2,500 for a 1300 sqf slab. I first put down plastic, then 2" pink foam $20 per sheet at Menards. Used staples to hold the pex to the foam, rebar on top of risers, then cement. Still holding together after 2 months... I ran the 2" foam from the bottom of slab up the side along my 8" block to the osb wall. I started to dig down a couple of feet below the slab so I could run the foam deeper, but did not like the dirt falling out from under the slab. Figured I might be doing more harm then good. Entire slab is then encased in the 2" foam, so should be good, i think...

 

[LS1NOVA]

From my understanding, you need to go down to the frost depth to prevent the slab from heaving. I was told 2ft and 4ft. Dont know which. I got all my radiant stuff from a local guy at cost (yes quality stuff) for $2100 including an electric boiler.

 

[badgerboiler]

When insulating a slab-on-grade structure the foundation type is the first question. Generally, the slab doesn't care if you protect it from frost by installing XPS insulation in, down or out.

Online DIY radiant floor heating venders can be a good thing, if they provide a heat load analysis and insulation specs before you buy.

http://www.badgerboilerservice.com/helpme.html

 

[leeklm]

From my understanding, you need to go down to the frost depth to prevent the slab from heaving. I was told 2ft and 4ft. Dont know which. I got all my radiant stuff from a local guy at cost (yes quality stuff) for $2100 including an electric boiler.

Let us know what you end up doing... Since we are both in the Mpls area, we will have to compare notes come January. Maybe I will be installing more XPS next spring I am going with natural gas, since Xcel does not seem to have a very attractive off-peak offering for residential use (at least compared to a friend of mine with Wright/Hennepin Electric).

 

[LS1NOVA]

Dug the trench today down 2ft and 3ft at the doorways that will have the snow removed. I used this little beauty! If I was rich, Id definately buy one.