How to use plastic as a Vapor Barrier in the Walls.

You don’t need a vapor retarder.The Class III vapor retarder range is between 1 and 10 perms, and even less water vapor will diffuse through it.The air leakage pathways should be sealed.

How do you fix a vapor barrier behind a house?If a vapor barrier is damaged during a repair, it may be patched with housewrap tape, but small holes only marginally impact effectiveness.It’s almost impossible to not damage the vapor barrier when patching on an exterior wall.

There is a paper lining on one side of the insulation.Even with faced insulation, some builders choose to attach a separate vapor barrier.It doesn’t hurt anything.The result is a super-insulated wall with a foam vapor barrier.

A vapor barrier should be placed on the warm side of your insulation to stop warm, moist air from condensation on a cold surface inside your wall.The vapor barrier should be on the inside of the insulation in cold climates like Canada.