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Is a sill seal membrane needed if sill plate is pressure treated lumber?

Is a sill seal membrane needed if sill plate is pressure treated lumber?

Old 09-20-18, 02:54 PM
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Is a sill seal membrane needed if sill plate is pressure treated lumber?

I did not install a sill seal membrane between the concrete foundation and the pressure treated sill plate. I know PT lumber resists rot caused by moisture and is rated for ground contact, so moisture from the concrete against the sill plate is not going to cause lot of damage. Can I just use concrete sealant caulk along the gaps between the plate and concrete instead of disassembling the the walls I already have framed on top of it, removing the bolt anchors, and installing a membrane? I want to know what good it will do if I install the membrane, given I already used PT lumber.
Old 09-20-18, 03:08 PM
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That's up to you. They did without for many hundreds of year not even p.t.. I was gov. taught to use termite shield. The flavor of the day, like is coffee good for you?
Old 09-20-18, 04:05 PM
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Since it's already down and built upon, just leave as is. Go ahead and use the caulk to seal the seams. When the lumber eventually roots out you won't be around to know about it.
Old 09-20-18, 04:28 PM
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You use a sill sealer gasket to help stop air from blowing under the plate... treated or not. Yes, all you can do now is caulk it.
Old 09-21-18, 07:18 AM
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If there is an inspection involved they have the final word.

As for caulking to seal air leaks continue up where the wall meets the sill and catch all butt joints both sill and framing. Houses leaks a lot more air than one would expect and during construction is the best time to do much sealing.


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