Concrete To Wood Membrane

TIMS

What is the best membrane to place between a plywood subfloor and a
2 3/4" concrete overlay? I have seen 30 LB felt used and heard that modified bitumen is also a good alternative, the floor is also going to have radiant heat tubes inbedded into it.
Thanks Tim

cleveman

This is interesting. Why are you pouring concrete instead of gypsum? Why not pour 4" and strip the floor? Are you building the walls on top of the concrete, or have they already been built?

Why do you want a membrane? What is below?

If this were a garage (unconditioned space) for exampe, then you would want some insulation underneath.

If you just want to uncouple, then I suppose plastic would work, or practically anything. 15 lb. felt or 30 lbs should be fine to uncouple.

What is your location?

TIMS

This is going to be a finished concrete floor in a residence.The home is in the design stage right now. This is going to be on the main floor over a basement.I only need to specify the membrane to have a barrier between the concrete and the plywood. I'm in Pueblo West, CO. and this is not common practice down here. Can a micro topping be placed over a gypsum floor and how would the price of that compare to just pouring concrete and and putting a nice finish on it? Also they want radiant heat tubes in the floor so the concrete was also mass for heat storage.