Caulking Inside and Outside Sill Plate at Slab
Cup
| Posted in General Questions on
New construction home. The framers did not install sill sealer. The sill plates are PT. Any issue with caulking dynaflex 230 both inside and outside where the plate meets the slab?
My main concern is moisture wicking causing the plate to rot if both sides are caulked, preventing moisture from escaping.
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Replies
Cup,
I'm tempted to say, "Not your problem." The framers goofed; omitting sill seal is a code violation. Make them jack up the house, install sill seal, and retrofit anchor bolts.
But you're probably too nice to tell the framers that.
Cup,
Sill-seal is used to stop moisture moving up into the framing from the concrete below. Sill gaskets are used as part of air-sealing. So you have a problem with the former, but whether they put a sill-seal in or not, you still need some strategy to air-seal the sill area. How you do that depends on where your air-barrier is, and how you intend to insulate and air-seal the rim joist area.
I would get this fixed now when it's an easier fix. Moisture will wick from the PT sill into the end grain of the non PT studs and sheathing at the base of the walls. Also, depending on the quality of the PT and moisture levels it may degrade considerably faster.
Best of luck with your build.
Glenn Mathewson, is a great code educator from Colorado, and he wrote a good article in JLC, or you could go directly to 2021 IRC R317.3
https://www.jlconline.com/how-to/framing/is-treated-wood-always-required-for-sills_o
https://codes.iccsafe.org/content/IRC2021P2/chapter-3-building-planning#IRC2021P2_Pt03_Ch03_SecR317
https://up.codes/s/protection-of-wood-and-wood-based-products-against-decay