foam board insulation for radiant floor

[wastntim]

I'm looking at big box stores and seeing $30 a sheet for 2" 4x8 sheets. Is this the price that I'm likely to pay?

Are there some cheaper brands that are just as good?

 

[Randy in Maine]

I bought mine at a place that sells masonary and sheetrock suupply house. I paid about $1 per square foot for the 2", but they delivered it for free.

I also used 6" x 6" wire mesh (no rebar) for something to attach the PEX tubing to. My 4000 psi concrete is 6" thick and has the fibergalss in the mix. If you intend to install a lift, you want to keep the PEX tubing 3' from the lift anchor locations.

 

[jack stand]

I found a place called "Insulation Depot". They sell used ridged foam insulation, mostly removed from commercial (flat) roof jobs, think walmart. The sheets have some fastener holes in them and some have chipped edges, but I bought 1 1/2" poly iso for about $9 4x8 sheet. Do a search and contact them to see if they have a location near you.

 

[kj_mustang]

I found a place called "Insulation Depot". They sell used ridged foam insulation, mostly removed from commercial (flat) roof jobs, think walmart. The sheets have some fastener holes in them and some have chipped edges, but I bought 1 1/2" poly iso for about $9 4x8 sheet. Do a search and contact them to see if they have a location near you.

You don't put poly iso under a slab. XPS or EPS go under a slab. I never could find it much cheaper for my project. I even priced EPS from a semi local manufacturing plant that will sell to the public and it was no cheaper. I opened a Home Depot credit account and used their 10% off first purchase deal to get it a little cheaper.