Does using Knauf Ecoseal allow the house to breathe?
Ashman80
| 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
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.
Excellant response Martin. You nailed it!