Basement Subfloor & Radiant Heat

[ryanandnina]

I am buying a new home with a semi-finished basement. I would like to gut it, UGL Dry-loc the walls and the floor, and install a radiant heat system & subfloor. I plan to then put pergo on the sub.
I'm not sure what the best way to do this is. I have gotten MANY differing opinions.. I had planned to glue and Hilti 2x4 sleepers every 16 directly to the sealed concrete. I then planned to cut 1 1/2" rigid foam insulation into strips, and install PEX Heat Transfer Plates for the tubing in between those. so it would go:

Sleeper...foam...tube down...foam...tube up...foam...sleeper.

Then planned to cover that with CDX then pergo.
I have been told the insulation will hinder the radiant heat's performance, also, I should just use warmboard (too expensive for this sized project), and many other things. Do I need anything else under the pergo? Is this a huge waste of time and money? I live in Maine and want to be able to spend time down there, and hot water baseboards just don't cut it for me.
ANY help would be greatly appreciated!

[roger g]

Have you thought about just attaching the piping to the existing concrete floor and pouring one and a half inches of the really runny lightweight cement on top. It's the same stuff we pour on a second floor over the sub floor. You can then either carpet it or whatever. Make sure you do separate zones and maybe some thermometer wells so you can regulate the floor temp.

Roger

[Rich]

Called gypcrete. We're doing that very thing (in about 7 months) on a project. We already have a structural slab - we will then put down 2x2 sleepers at 24" o.c. radiant piping goes between sleepers - manifolds go in walls behind access doors. Pour 1.5" gypcrete then put 3/4" plywood down attached to sleepers. Wood planking goes over plywood. Walls, of course would already be framed with double bottom plates. This is an acceptable installation method from the piping system manufactuer - Wirsbo.

[ryanandnina]

I looked at pouring a new concrete/gypcrete floor, but the response times were a bit slower than I wanted.

[Rich]

Seems like the warmboard panels (or I think there's one more different type too) would save time and maybe money in the long run. I don't really see how the insulation you mentioned is going to hinder the performance - other than maybe it will hold the heat in and slow the systems heat / cool cycle down.

[roger g]

I've never seen it done with the "sleepers" but I understand the concept. Normally I've seen them put hardwood floor right on the 'crete though I didn't take any notice as to how the wood flooring went down. I assumed it was floating somehow.
Too bad they hadn't put the pex under the original concrete floor. We did some jobs for some contractors and we put pex under all the concrete floors regardless of whether they were going to heat the floors. It's similar to a bathroom rough in, in the basement where it can be done at any time in the future by any owner. We even put loops in the garage floor just in case someone in the future wanted it. It's a lot cheaper to do it then and evidently it became quite a selling feature for the contractor. He could show perspective owners that he planned ahead.

Roger