radiant heat in floors

What have I done

I am redoing a kitchen and 2 baths in our old farmhouse. While I have the floors and everything gutted I want to add radiant heat to the floors.

The kitchen has a crawl space underneath,very tight. I was thinking putting the radiant above the existing subfloor. What are your opinions on the best way to do this? I priced warmboard and it seems very expensive for my budget.
Heres my thoughts, let me know what you think. Putting down aluminum coil stock over the entire floor for heat transfer. Cutting 5/8" cement board into 7" strips. fasten cement board strips down allowing 1/2" between rows for the pex. Install pex between rows of cement board and cover the rows with gypcrete or thinset. Top it all off with ceramic floor.

Thoughts or problems come to mind????????? THANKS

RemodelMan

You should look into a contactor that will pour "Gyp-Span" or "Firm-Fill".
Both are self leveling, set up in less than a 1/2 hour and lighter than cement.

undone

How high in elivation can you go on these floors? I've been getting more and more involved in putting down Pex tubing and running hot water through it to heat spaces--very impressive performance!