New slab with radiant heat
As part of our remodel north of San Francisco (ZIP code 94941), we are converting about 700SF of our lower level into living space. The existing slab has been removed we excavated a few additional inches to increase our ceiling height, and we are getting ready to put back a new 5″ slab, in which we will also add radiant heat tied to the rebar.
I just now came across some information, such as Polyethylene Under Concrete Slabs and Polyethylene under slabs – no blotter sand, that are worrisome to me, since they seem contradict the design that our architect has come up with.
What our architect has called for is (from top to bottom):
- Conc Slab, SSD
- 1″ Rigid Insulation
- Min 6Mil WPM
- 2″ Sand
- 6″ Crushed Rock
- 4″Dia Perforated Pipe Foundation Drain
The slab is going to be 5″.
I have also attached an image of the new slab detail.
Is the above the right layer structure or do we need to revise?
One thing we do not want to change is the concrete slab and radiant heat in it. So I’m basically interested in what should go below the slab at this point.
We really don’t want to have to worry about ever touching that slab again!