Dormer Ceiling Vapor Barrier Artis Bedrooms August 19, 2017September 26, 2017 0 Comment The dormer’s ceiling had already been insulated with polystyrene so I installed 4 mil plastic for a vapor barrier. This is our sitting area for rest times from work. Dormer Rest Area Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Like this:Like Loading... Related