vapor barrier under concrete slab

DIY1

I'm pouring my basement floor/slab in a few days and I had a question. My architect recommended a 10 mil sheet of poly under the slab as a vapor barrier. I'm not going to be able to get a 10 mil sheet by that time but I was wondering if it would be ok if I took two 6 mil sheets and used some sort of silicon around the edges to basically seal them as one sheet. Would this double ply 6 mil basically be the same as a 12 mil sheet (assuming I can keep the moisture from getting in between the 2 sheets)?

Mort

How come you can't get the 10mm? We have 10mm at work, and haul it to jobs all the time. Call your concrete supplier and see if they have any.

cleveman

Yeah, you can do the two layers if you must.

joecaption

Two layers will work and there's no need to try and use silicon.

jomama45

Ditto...........

Gary in WA

Don't sweat the small stuff; http://www.greenbuildingadvisor.com/...cience-podcast

This was next to that one in my library; http://www.nrmca.org/aboutconcrete/cips/29p.pdf

And the perimeter insulation per code, if in a heating climate; http://www.buildingscience.com/docum...059-slab-happy

Gary

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TRUEPRO

Cant they invent insulated concrete?

Mort

I'm going to invent self-heating concrete, so I don't have to drive on friggin' snow for 4-5 months out of the year.

TRUEPRO

Electricity heats the roads, heat melts the ice, melted snow drains in reservoir, reservoir feeds turbine, turbine sends electricity to power road heat. Genius