Insulating Garage Floor

bob the builder

I will be turning a 30'x24' garage into a family room. Originally we were going to do radiant floor heating and pour some gypsum crete over it. Well the price was a bit to high for the customer so now they just want a treated 2x4(after floor leveling) floor insulated. I am leaning toward using a foilfaced foam board for a higher r-value. From what I remember I will be losing a little r-value in a few years, but over all it seems to me like a good route to take.

My only concern is after I lay a vapor barrier and install subfloor should I be concerned about moisture getting trapped underneath the floor?

Thanx, Bob

naildriver

Bob just happen to have enclosed a garage about 2 months ago. After framing our floor with 2x10 joist we spread 6 mil. plastic over the concrete slab and used faced r-19 insulation. Had to lay in the insulation before we subfloored but worked the best. The homeowner raves about how tight the room is, as a matter of fact she installed a wall mount gas heater to help with the warmth and last week a couple of nights the temp got into the lower twentys and she said the heater came on once all day. Hope that this helps you in some way.