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Re: SLAB ON GRADE

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Speaking from Oregon - the problem you describe only occurs when the sand
layer is saturated prior to placing concrete...i.e. heavy rain the night
before which doesn't leak out through all the (inevitable) holes in the
vapor barrier.  Or, occaissionally if the contractor pre-wets the sand too
much (almost never happens).

I like the sand layer, but occaisionally allow the contractor to omit, when
done in written RFI's, so I can place the risk exactly where it belongs.

I have seen SOG problems when placed directly on vapor barrier in summertime
80deg+ breezy conditions, but such cracking is only slightly related to the
water which may migrate up from below.

You need to understand what floor covering and method is to be used on your
SOG, and what time of year placement will occur.

Larry Oeth
----- Original Message -----
From: <NDZ28(--nospam--at)aol.com>
To: <seaint(--nospam--at)seaint.org>
Sent: Tuesday, April 25, 2000 9:35 AM
Subject: SLAB ON GRADE


> Just hoping I can get a basic question clarified. I  have a client  I'm
doing
> a series of homes for, and he wants me to specify that the slab on grade
be
> placed directly over the vapor barrier, (no sand between) He claims that
when
> sand over the vapor barrier is moistened prior to pouring concrete, sand
will
>  never dry out,  the moisture from the sand will travel through the slab
for
> a very long time causing bubbleing in the vinyl flooring, prevents  wood
> flooring from sticking to concrete, etc. I've always believed that the
sand
> aids the curing of the slab.  The caveat is that vapor barrier is
installed
> properly and not punctured during placement of concrete. Any help is
> appreciated.
> Andy Vidikan
>
>