When did sill seal under the sill plate become required in bldg codes?
In a small (825 ft.²) 1979, slab-on-grade house in urban Oregon that I did blower tests on, I’m finding readings that seem surprisingly high (~850 CFM50), though the house has good (and few) windows and good door seals. I addressed some attic leaks (and there are more), but the reading still seems oddly high.
That got me thinking the sill plates may not have been sealed during construction. This is a tract/subdivision house, built with many similar others on its street. I’m wondering when sill sealing, by any means, came into vogue in the building codes. ??
A few bore scope viewings are not conclusive. Could I reduce air leakage by silicone caulking the sill plate? I’d work from the inside, since the crap carpeting wasn’t tacked in well and all I’d have to do it pull the cheap floor molding strips, vacuum up debris, and maybe bl0w-dust a bit for a clean caulking surface.
Thoughts??
Cheers!
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I sill sealed, from the inside, with caulk and spray foam, a 1996 slab on grade house, and it made a HUGE difference in comfort. I did mine when I removed the carpet to install hardwoods, but even if you put the carpet back it's worth it. The difference was actually shocking. It can't hurt, so I suggest you do this.
Benergy,
Sill seal and sill sealing are two different things. Sill seal - usually a plastic gasket under sill plates - is primary there as a capillary break to stop moisture movement. An emphasis on air-sealing is relatively speaking a new thing. When I went to architecture school in the early 80's we were taught about poly as a vapour-barrier, but there was no mention of air-sealing being important.
The low hanging fruit for improvements in air-tightness on a slab house are typically the ceiling, and the bottom-plate.