White poly under concrete ?

Mudball

Anyone against the white poly on one side for the bubble insulation for under concrete slab ? Everything Ive read thus far says that the lime in the concrete will eat most bubble foil materials and thats what the one side of poly is for. I was going to use it for what little R-value it will have but also as a moisture/vapor/radon break. Any other products I need to consider ?

Bob Mariani

Better to use 6 mil black poly but you can use the white

Gary in WA

Rigid foam board (2") insulation around perimeter (Or as local Building Department requirements) and air seal the plastic: http://www.100khouse.com/2009/06/24/...b-air-sealing/
Don’t use loose sand in certain applications: http://www.stellarcontractors.com/as...loose_sand.pdf


Be safe, Gary

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Mudball

Thanks for the responses and the links. Great information.
This link shows two examples of the products I was talking about.
http://www.buyfoilinsulation.com/und...ation-c-8.html

Gary in WA

I'm not entirely familiar with that product but suggest you research it more. Foil needs an air space to insulate, not touching: "Underslab insulation is typically of the polystyrene board type where R-values greater than R-1.5 are specified. Reflective foil insulation, on the other hand, requires an air space to be effective although some foil products are approved for underslab applications. R-values on these products are generally R-1.5 or less." From: http://www.radiantpanelassociation.o...cfm?pageid=420

1-4" of dead air space in a wall cavity is R-1. 2" of the pink foam is R-10.

http://www.greenbuildingtalk.com/For...c/Default.aspx

This I found with a short search: http://www.healthyheating.com/Page%2...o_bldg_sys.htm

Be safe, Gary

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stuart45

Interesting that you put the sand on top of the poly DPM. We put the sand below the poly to cover the hardcore.

The insulation is also put between the slab and wall now, as this is an older diagram.

Mudball

Well very interesting indeed. I have been reading and researching for the last 1-1/2 hours since I read your posts. In short I can say that Im now 99.99% sure we wont be using bubble foil under the concrete slab.
Thanks for the help.

itsreallyconc

stego 15mil vapor barrier's the current spec by architects/engineers

Mudball

Oh yes itsrealltconc. Ive come back to the yellow stuff a couple of times. Ive already called them last week and they have given me two different suppliers in my area. I will give the suppliers a call this week. I just hope I dont get sticker shock $$$$
Thanks for the help

jomama45

Don't worry, you will.

Far more expensive than 6 mil poly in my experience. Unless you have a known radon problem, I'd steer towards the 6 mil.

Gary in WA

http://energy.cr.usgs.gov/radon/rnus.html
Be safe, Gary

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Mudball

Thanks for the help and the link. I bought a roll of the stego 15 mil today for 225.00 and that was worth it to me. It is 2.5 times as thick as the 6 mil and when you take the 94.00 I paid for the 6 mil (94 X 2.5 = 235) then it comes close to the same or actually a little better pound for pound for what your getting. I feel much better with this product under the slab.
Thanks again.