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Community and Q&A

Caulking for sill plate

JSPIV | Posted in General Questions on

I was going to caulk the exterior joints of mud sill as an extra precaution (it just had standard foam sill sealer under it). Is a standard caulk made for these substrates (such as Contega HF) suitable for this? Or is it better to use a vapor open product such as Prosoco or tape?

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  1. drewintoledo | | #1

    I don't think vapor perm is important for this application. You want something that will move. My experience is to use a low modulus sealant something such as an acoustic sealant or such. I wanted a VERY tight seal so I placed two beads, laid a foam gasket, and then two more beads on top. Of course, that's overkill.

  2. Expert Member


    Contega HF is often recommended here as a more benign version of Tremco acoustical sealant.

  3. PAUL KUENN | | #3

    Under the plate we use lots of Tremco's accoustic sealant but for really bad foundations I like a bead of Contega HF on the outside.

  4. JSPIV | | #4

    Thanks all. Yeah this is an exterior application to the seam, as the mud sill has already been installed. Sounds like something like Contega is a good fit. I read so much about vapor permeability... I just think I started overthinking it..

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