Photo Source: Summerhill

Installing the vapour retarder and/or air barrier:

Polyethylene installed on the interior of the building can act as both the vapour retarder and the air barrier.

Sheets of polyethylene (poly) will be installed on the interior of the home after the insulation is in place. It will cover the walls and all exposed ceilings throughout the home. When installing, cover the entire area and fasten to studs, strapping or joists using staples as you go. Make sure that the polyethylene is tightly fastened and that it is flush against the studs and insulation.

Hint: Using dry wall stilts or a long object such as a level can help make the installation process easier. Hanging the poly first without securing within 12" of joints, penetrations, etc. will make it easier to add the sealant later on.