Interior Wall Insulation Vapor Barrier

Any condensation on a properly installed continuous plastic vapor barrier will.

Interior wall insulation vapor barrier.

In any case the vapor barrier must point to the warm side. A continuous plastic vapor barrier prevents condensation from forming on the internal surfaces of the exterior wall. And to be clear you absolutely need a vapor control layer of some kind on the warm side of the insulation to be compliant with canadian building code. Usually composed of a thin film such as polyethylene vapor barriers are used to retard or prevent water vapor diffusion into a wall ceiling or floor during the cold winter.

In an unoccupied space you need an ignition barrier adjacent to either low density or medium density foam this could be an intumescent paint or from the list in r316 5 3 depending on the spray foam section of your local code. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. See each icynene spray foam product to check which paint on or spray on ignition barriers can be used. This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses.

Better still that inboard air barrier can now also serve as the vapor control layer with products such as intello plus or db that double as smart vapor retarders and airtight membranes. Installing a vapor barrier on the warm interior wall of your cement brick house will prevent condensation and reduce air leakage through your walls and insulation. The performance of these materials is gauged by their water vapor transmission rate or permeance. As a result by keeping conditioned and moist air out of the insulated enclosure airtight smart vapor retarders can provide robust protection from moisture damages for the life of the building.

Using vek type products serves very little purpose on the interior walls. Not every wall does. If you install the vapor barrier on the cold side of the insulation i e the inside of the brick you will trap moisture inside the walls and make the moisture problems worse. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets.

What you see on the interior of that diagram is the netting that holds the cellulose in place while allowing air to escape during injection followed by a poly vapor barrier strapping and drywall. Zone 4 marine requires a class iii or lower vapor retarder on the interior surface of insulation in insulated wall and floor assemblies where the permeance of the exterior sheathing is 0 1 perm or less as tested by test method b the wet cup method of astm e 96 and the interior surface of the exterior sheathing shall be maintained above the dew point temperature of the interior air. Vapor barriers on the interior and exterior walls is desired no matter if you insulate or not. If you don t insulate your walls vapor barrier on the inside walls is ok.

Here goes the vapor barrier rules.