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Community and Q&A

Does using Knauf Ecoseal allow the house to breathe?

Ash Bryks | Posted in Green Products and Materials on

I live in Alberta, Canada, and am building a new house. The builder introduced me to the Ecoseal product which sounds great. As my knowledge on construction is limited, I have a question. If there is Ecoseal applied and batting along with a vapour barrier, can the wall still breathe to eliminate moisture, thus not having mold concerns 5 years down the road like open-cell foams?

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Ash,
    I'm not sure what you mean when you ask, "Can the wall still breathe?" There is no technical meaning to the word "breathe" or "breathable."

    Some people think that a "breathable" wall leaks air. Other people think that a "breathable" wall is vapor-permeable.

    If you want your wall to leak air, don't install Knauf EcoSeal. EcoSeal is designed to seal air leaks. For more information on EcoSeal, see Air Sealing With Sprayable Caulk.

    I should point out, however, that it would be stupid to build a leaky wall on purpose. Sealing air leaks is a good thing to do.

    EcoSeal is a water-based latex caulk. It is somewhat permeable to water vapor; its permeance will vary depending on its thickness. However, its vapor permeance is irrelevant, because it isn't installed as a complete layer -- only in thin bands to cover cracks. The permeance of your wall sheathing -- not the permeance of the EcoSeal -- will determine whether or not your wall assembly dries to the exterior.

    Finally, products that are vapor-permeable aren't always better than products that are vapor-impermeable. In the case of open-cell spray foam, which you mention, there are roofs that are rotting because open-cell spray foam was chosen instead of closed-cell spray foam (a vapor-impermeable choice). For more information on this issue, see Open-Cell Spray Foam and Damp Roof Sheathing.

  2. Chris Brown | | #2

    Excellant response Martin. You nailed it!

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