Vapor retarder / Green Building & Sustainable Home Renovation Information & Advice

...vapor control layer In cold climates, the conventional vapor control layer is typically installed on the warm side of the wall assembly, which means the interior side of the studs. This could be a 6-mil polyethylene sheet (Canada/Northern US) or a smart vapor retarder. The moment a vapor control layer is introduced, it...

Vapor open membranes and smart vapor barriers: what they are and when to use them Vapor variable membranes, often called smart vapor barriers or vapor open membranes, are one of the most significant advances in modern building science. They look like standard vapor barriers but can allow a certain amount of moisture to...

...vapor barrier, meaning it allows moisture to pass through. This can be beneficial in some applications, such as attic spaces, where controlled moisture permeability helps prevent trapped condensation. But for walls it means you still a vapor barrier or vapor retarder depending on your climate. Closed-cell spray foam ac...

...retarder. Click image to enlarge Interior insulation only: mineral wool board or EPS foam as thermal break against concrete wall 2x4 stud wall with mineral wool batts in cavities drywall with latex paint as vapour retarder. Note: Not having proper exterior moisture protection for this wall assembly will mean moist...

...vapor barriers The job of a vapor barrier is to prevent vapor diffusion, and the job of an air barrier is to stop air leakage through differences in air pressure. A wall system should have one vapor barrier, but can have many air barriers. A vapor barrier can act as a very effective air barrier, but an air barrier does...