I have a tongue and groove wood floor over a dirt filled crawl space and I don't want to rip up the floor to insulate. I am going to put cement baord down and tile the top with granite using an underfloor heating mat since there's no heat in that part of the house.
Can I put some kinds of foil between the wood and the cement board to keep the heat in the house? Any ideas? I have seen 2 kinds of foil one that looks like bubble wrap and another that's like think kitchen foil. I was thinking the bubble wrap would cause too much give and make the tile crack?
Would the foil cause any kind of moisture problems that would rot out the wood?
Help!