Vapor-smart Insulation

摘要

Several years ago, we told readers about a CertainTeed vapor-retarder sheeting called MemBrain (FHB #165, p. 38). When applied over unfaced insulation, this "smart" vapor retarder reduces the chances of condensation in the wall cavity by allowing water vapor to escape when relative humidity is high and by blocking moisture from entering the cavity and condensing when humidity is low. Now CertainTeed is offering Dry Right insulation, conventional fiberglass batts faced with a thin layer of MemBrain instead of the familiar kraft-paper or foil facing. Dry Right is friction-fit between studs or joists, so no stapling is required. Dry Right batts and rolls are available in standard sizes with R-values ranging from R-13 to R-19. They cost a bit more than conventional fiberglass insulation, but Dry Right should help to keep wall cavities dry and mold-free.