Correct basement slab poly install
sirraf69
| Posted in Green Building Techniques on
Getting ready to start a new home and have a few questions about the basement slab. I understand I need the gravel put down first, then XPS, and then vapor barrier before the slab. I keep reading about many different kinds of poly to use as the vapor barrier. I have found this poly and was wondering if it will be suitable? It is Grip Rite 10 mil clear poly sheeting, and it is made from virgin resins. I have also read that it must be black colored poly under the slab. Does the color really make a difference? Thanks for any input/suggestions.
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I don't think black matters under a slab. I do think it matters in a crawl space, where light coming through a vent can cause things to grow under clear plastic. Don't know what the Grip Rite costs, but I have used Stego (which is yellow) and it is a bombproof material.
The grip rite is around $140 for a 20X100 roll. I have seen the Stego on the web, but can't find any prices on it. I would want enough to go under my basement(2000sf) and garage(668sf). I guess I was concerned that the grip rite was not ASTM E-1745 rated. Thanks for the response.
Stego costs significantly more than that, I think. Last I bought was 15 mil, probably in the $3-4/sf range.
Whether the extra thickness makes a big difference in the average residential installation... who knows. Stego is stuff you can drive an excavator on. It is easily possible to place typical 6 mil poly over foam, tie rebar, and then pour concrete without tearing the plastic. I don't know if the extra mils get you measurably better moisture performance for most jobs. The available tape and mastic are useful.
So I guess the grip rite would be okay to use? I was thinking the 10 mil would give me a little extra strength. When it goes down, should it also go up the basement walls 4 inches so that it covers the edges of the basement slab?
Sto-Cote Tu-Tuf
... for under slab, as a ground top crawl space moisture barrier and for outside and inside air and vapor sealing of crawlspaces.
Can buy different dimensions on Amazon.com
That Tu-Tuf is much higher than the Grip Rite. I'm just curious if the Grip Rite would be a good product to use?