Stainless Steel Mastic Strips for Termite Barrier
I assume many of you read Joe Lstiburek’s ‘Building Science Insights.’
In BSI-118, Concrete Solutions, he references a mastic strip containing stainless mesh to act as a capillary break for the foundation wall and block termites.
Does anybody know of any actual products for this? Or is he combining multiple products to achieve this?
See quote below:
And you need to seal the top of the slab – across the rigid insulation bond break – to the top of the stem wall using a masticed stainless steel mesh membrane strip. This is – and I use the next word with emphasis – absolutely necessary to provide a “termite barrier” and “insect barrier” and to provide air control layer continuity between the perimeter wall and the slab itself which is acting as the air control layer of the foundation.[3]
https://www.buildingscience.com/documents/building-science-insights/bsi-118-concrete-solutions
This concept does seem like a good method. The termite zones are inevitably creeping further north also.
Thanks
Malcolm
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Replies
Did you find out anything about this? I'm wondering the same thing.
Janet McIlvaine [email protected]
Yes, this is two separate products used together. The SS termite mesh is sold under the trade name "Termimesh" . There might be others. Joe's recommendation refers to installation of Termimesh in the gap and using mastic to adhere and seal it to the materials on both sides. The mastic can be asphalt-based or other depending on application.
The details show a 2x6 bottom plate supported by 3-1/2" of stem wall and 2" of rigid insulation. Does the code support 2" of sill plate cantilever or is this something an engineer would have to seal?
That would be up to the local authorities. I would argue that the studs still have as much bearing as standard 2x4 studs, so the cantilevered part really makes no difference. You could cantilever them out a foot and the stresses really wouldn't change in any big way.
Carl Seville used Polyguard on his new house. What you are describing sounds like #7 on this page: https://www.polyguardproducts.com/term/structures/residential-structures/.
Thanks for the replies. Yes I've seen Termimesh. Does it come in strips that fit under a sill plate? And can you easily purchase it or do you need an accredited installer to do it for you?
I've also seen the polyguard products. Seems like they have some good stuff. Sealing the slab under the exterior sills is great, but of course you need to install another seal to block air infiltration between the tape and the framing, unless you're doing that at the sheathing layer I guess.
Termimesh comes in rolls that can be cut into pretty much any shape with normal snips. I don't think you need any particular accreditation, but you'll have to check on that. Finding a supplier might be an issue, but contact the manufacturer and see what you can get.
I don't have any experience with the Polyguard products, but they look very interesting. It looks like their sill seal product includes air/moisture/termite protection in a single product. nice idea. Their base flashing then completes the air/water/termite barrier for the base of the sheathing.