I'm looking at converting my attached garage (14 x 20) to a more usable living space. The current concrete floor is a mess and a new surface is necessary. I currently have hot water heat in the house and I was looking at putting a 250' loop in the garage to heat the floor. I was planning on doing the following (keeping in mind that my max increase in floor height is 2"): 1. Delta FL or similar dimple membrane 2. Foil/Foil bubble insulation 3. Plywood ripped/routed to put in 5/8 pex with the possibility of putting in some aluminum in the channels (I would like to use warmboard but the prices appear to be a little over the top) 4. Engineered wood flooring Any thoughts? Has anyone tried this with any success? Thanks

You can't choose a heating system until you have a heat load performed. Bubble foil, routing, sand, DIY aluminum channels tells me you are looking at the wrong web site.

bubble foil is a complete waste of money. anyone claiming otherwise is,.... ahem... selling something. probably bubble foil.

no need for 5/8" pipe, it won't help. stick with 1/2".

you want at least a 1/2" foam thermal break to the existing slab, and more is generally better.

I have tried to calculate Head Load as suggested but each online calculator gives me different results....here's some more info on the room
14 x 22 (9 high) with 20 sq of windows (2 pane with low E) a 7x9 garage door (r 12) and 40 sq of door ( r 8) the ceiling is insulated and the one long wall is shared with the main house. I have a 100000 btu boiler (81 000 btu actual) and my house currently has a load of 27600 btu (calculated at 600 btu/foot of radiator). Is there a site where I can visit to get more info on determining infloor requirements. (I only want the room to maintain a temp of 65 F).

Thanks