Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Fwd: Re: Location of Vapor Barrier Below Concrete Slab on Grade

[Subject Prev][Subject Next][Thread Prev][Thread Next]
For the practical application of it, always place the vapor barrier below a
3" sand cushion. That way it does not get damaged while pouring.


At 05:12 PM 2/18/97 -0500, you wrote:
>Can anyone provide comments on the specific advantages/disadvantages of
>placing a slab on grade vapor barrier directly underneath the concrete slab
>or below a 3" sand cushion?
>We are designing a slab on grade system for a office/warehouse facility for
>which the Geotechnical report does not require the installation of a vapor
>barrier.  However, the flooring system the tenant requires will only
>install/warranty their product if a vapor barrier is provided.  The vapor
>barrier system they would like to use ("Premoulded Membrane Vapor Seal" from
>W.R. Meadows or "Moistop" from Fortifiber) recommends placing the vapor
>barrier directly below the concrete slab while specifying a concrete mix
>as low a water-cement ratio as practical, low slump, and wet curing to
>differential shrinkage and slab edge curling.  ACI and PCA recommend a 3"
>sand cushion to reduce differential shrinkage and curling regardless of the
>type of vapor barrier used.
>Please respond ASAP.  Thank you.
>John Carroll, Structural Engineer
>The McSherry Group, Inc.
>email:  mcsherrygp(--nospam--at)

--- Internet Message Header Follows ---
Received: from ( [])
	by (8.8.5/8.8.5) with SMTP id UAA00866
	for <rlewis(--nospam--at)>; Tue, 18 Feb 1997 20:54:15 -0600 (CST)
Received: from by (NTList 3.02.10) id
ga004036; Tue, 18 Feb 1997 18:48:42 -0800
Message-Id: <>
X-Sender: seaoc-ad(--nospam--at)
X-Mailer: Windows Eudora Pro Version 3.0 (32)
Date: Tue, 18 Feb 1997 18:42:04 -0800
To: seaoc(--nospam--at)
From: Shafat Qazi <seaoc-ad(--nospam--at)>
Subject: Re: Location of Vapor Barrier Below Concrete Slab on Grade
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Reply-To: seaoc(--nospam--at)
Error-To: seaoc-ad(--nospam--at)
X-Loop: seaoc(--nospam--at)
X-Info: [SEAOC]
Owner: seaoc-ad(--nospam--at)
X-POP3-Rcpt: seaoc-ad(--nospam--at)
Precedence: list
X-ListMember: rlewis(--nospam--at) [seaoc(--nospam--at)]


Richard Lewis, P.E.
Missionary TECH Team

The service mission like-minded Christian organizations
may turn to for technical assistance and know-how.