Are polyethylene "backer rod" gaskets OK? They are available in diameters
from 1/4" up to 2" for a few cents a foot from concrete and masonry
suppliers. They are somewhat compressible and make good stuffers for larger
cracks like windows to rough openings. They are intended as dams to prevent
caulk sealants from sucking down into a wide gap before they can set up.
When blower door testing houses, the backer rods look fairly tight even
before caulk is applied over them.
Mike
>
>The best solution to the problem you raised regarding chemical
>sensitivity to liquid sealants is probably the use of extruded
>thermoset (e.g., EPDM or silicone) gaskets. PVC, urethane and
>santoprene are also available in various profiles, foamed and
>otherwise, but would are less desirable because they are not as
>inert as the thermoset resins. EPDM gaskets are used on a
>widespread basis in manufactured Housing in Europe (esp. Norway,
>Sweden, etc,) and also in most european windows. In the US liquid
>sealants are usually preferred for these applications, with
>associated off-gassing of solvents and other additives for months
>or even years. The chemicals off-gassed by some are proabably
>more offensive than others, however and the specific sensitivity
>seems to be a very individual thing.
>
>Unfortunately, this solution may not be at all helpful in a
>retrofit situation such as the one you currently face. The EPDM
>gaskets are typically placed during construction (e.g., between
>sill plate and floor, between wall sections, etc.) and do not lend
>themselves to remedial application. I would suggest a painstaking
>process of testing various inert foam materials (which can be
>forced into gaps) for sensitivity to the client. You probably
>will not be successful in completely plugging all of the holes but
>you may be able to get most of them. Be sure to deal with leaks
>around interior wall surface penetrations such as electrical
>outlets, lights, piping and fans. A variety of products are
>available for this purpose and should work in a remedial
>application.
>
>As to the most natural material which can be found for this
>purpose_ because of the growing number of people with MCS
>(multiple chemical sensitivity)_and I have become one_ many
>plastic product applications are being replaced with natural
>rubber materials. I am not aware of any extruded gaskets or
>sealants currently available in a natural rubber material, but if
>not, one might bring it to the attention of a manufacturer such
>as Monsanto (a large manufacturer of foamed gaskets and
>weatherstripping). Who knows_ they might very well decide to make
>such a product. Hope this helps. This is probably a good subject
>for EBN if they haven't already addressed it. Nadav?
>
>
>_____________________________________
>Loren E. Abraham, AIA, IDSA
>President - DTI/ERG
>912 St Charles Avenue, Charlottesville, VA 22901
>Vc: 804 296 4197 Pg: 804 963 1511 Fax: 804 971 3729
>© 1997 Daybreak Technologies Inc. / Environmental Research Group
>
>
>You wrote:
>----------
>> From: Marc.J.Rosenbaum@valley.net (Marc J. Rosenbaum)
>> To: greenbuilding@crest.org
>> Subject: GBlist: Natural sealants
>> Date: 21 Feb 97 08:10:42 EST
>>
>> I have a building to fix where the owner was fanatical about
>everything being
>> natural and non-toxic. The problem is, it is incredibly leaky.
>What
>> substances are natural sealants, replacing caulks? Need to
>accommodate
>> movement, etc.
>>
>> Marc
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