We have a sun room that we're turning into heated space. There is a concrete slab, probably over sand or dirt. Instead of having to build the floor up to accomadate and insulation barrier, can we just seal the concrete, to avoid any moisture problems, then put in some type of insulation (what type is best?) and then install tile? Will there be a big loss of heat into the ground?
Also, is the mesh with the heat strips in it okay or do we need to go with coils?
You will alway want to lay out ome kind of insulation or yes, you will lose a considerable amount of heat to the earth. We have done successfully this way:
Roll out Northeastern Ohio Foam Products (NOFP.COM) "The Barrier". It is 3/8" thick poly insulator with a vapor barrier already attached and sealed at the edges. Then float (or nail) 3/4" plywood on top of that. Total added floor height (7/8").
Then staple Zmesh (25 year) low voltage heating element on top of the plywood. If you want a floating wood or solid wood, just install it directly over the zmesh. If you want to use a carpet over the top of the Zmesh, you will need to lay another 1/8" leuon or cheap plywood over the top of the Zmesh to protect it from the carpet removal in 10 years.
Tile will transfer the heat faster for a quicker reaction time but it will also lose it faster. If you have the option and can use carpet or wood, you'll be happier with it over the long run...IMO.