For an exterior concrete slab, does vapor barier go between the concrete and the stone base or under the base?

Answer 1

if you are pouring a slab for a building in a wet area then you can put the vapor barrier on the gravel or under the only thing is to keep it from getting a hole some times you can put sand on the vapor barrier over the gravel but you don't need it unless you are worried about water coming up through it

Answer 2

Concrete acts like a wick, or straw, and literally sucks moisture up thru it. Every single manufactured home builder I have come in contact with recommends a moisture barrier, even over the concrete, in a crawl space. Laminated flooring manufacturers demand a moisture barrier between concrete, and their product, or you will void the warranty. You can place the vapor barrier under the stone, if it is a thick membrane, and tough. The rocks will tend to tear it. You might even consider 2 layers, and offset the seams. Also, the edges of the concrete need to be sealed/water proofed, or you can have leach effect around the perimeter.

If youve ever seen a garage floor with white bleach spots, youve seen the effect of moisture leaching thru the concrete.

Good Luck

Answer 3

Between the base and the concrete, the idea of a barrier is to keep moisture from rising through the slab and it does.Also Ive seen where a barrier wasn't used and water leached through a crack in the slab every time there was a heavy rain. There is no guarantee the slab wont crack it happens often.

Answer 4

No vapor barrier needed for pouring a concrete slab.

Answer 5

Never heard of a vapour barrier under concrete. If they did that under houses then it would trap all the water under the floor and the house would "float" on the water traped under it. Just make shure you have a good base of stone and the right mix for your application. You might want to check out this site, it may help. http://www.concretenetwork.com/

Answer 6

No plastic needed for exterior concrete

Answer 7

put down your gravel then put down your plastic and then put down your steel or wire mesh, then pour your concrete! Good Luck!