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Discussion Starter · #1 ·
Hey, I normally hangout in the masonry section but I do have a question regarding poly vapour barrier under concrete.
I am pouring a basement floor for a friend, I don't normally do floors just small side walks, kerbs, the odd step or two.
The specs on the drawing calls for 3" of 15mpa concrete with poly, but I was told that the code here in Ontario says if the concrete strength is 25 mpa or more there is no need for poly.

I also understand it takes a lot longer to finish the concrete with ploy as the water has no where to escape.

Anyone got any additional info on this.
Thanks.
 

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Put the super 6 down, it prevents moisture escaping during the cure, your correct if can slow the cure down, but I would not call it a measurable amount of time, there are so many variables which can affect how long before you can get on the slab and finish it.

After the cure it prevents below slab moisture from coming up through the slab
 

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I put poly under all of our slabs.

You don't want the subgrade pulling the water out of the concrete.

Any dry or wet areas in the subgrade will cause the slab to cure unevenly, you can end up with dry spots while the rest of the slab is still too soft work.

I have never heard of eliminating poly based on the strength of the mix.
 

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Discussion Starter · #5 ·
Thanks I have never heard of it either, one last thing I would think putting it on top of the gravel would be the right thing to do is this correct.
 
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