Roxul Vapor Barrier Attic

Polyethylene is a plastic sheet that serves as a vapor barrier to resist diffusion of vapor and moisture through wall roof and floor assemblies.

Roxul vapor barrier attic.

For ceilings with sheetrock already and just a crawlspace or attic above it is our understanding from various research that there should be no vapor barrier on top of the roxul batts laid on top of the sheetrocked ceiling. Youll see that i mention roxul a lot in that tutorial but roxul is exactly the same as rockwool. 2 4 insulation has an r value of 13 5. Depending on the situation you may need to install an independent permeable membrane to serve as a vapor barrier.

In circumstances where conditions inside a home or office are much different than outdoor conditions water. The need for installing a vapor barrier depends on the climate zone of the building. I chose to insulate with roxul which has a higher r value than the pink stuff. I ve read that i need to use a vapor barrier but i ve also read that vapor barriers can cause houses to be moldy or can cause rot inside the walls because the walls cannot dry out properly.

Whether you are building new or renovating your home use roxul comfortbatt thermal home insulation in your exterior walls attic ceiling and floor frames for top thermal performance. And by the way if you re remodeling a shower and use rockwool with kerdi board or wedi s shower system there s no need for a vapor barrier. I am in zone 4 right on the edge of zone 5 in long island ny. A well insulated side attic.

This is primarily due to the kerdi board or wedi. With 2 layers between the joists and another layer running perpendicular over top the r value of the insulation in the side attic is in the range of r 40. Some debate still occurs over how necessary vapor barriers are but a consensus is growing closer. Note that rock wool insulation only comes un faced meaning there s no kraft paper or foil barrier.

Resolution of the vapor barrier debate. Roxul batts are made of mineral wool and don t support moisture like say recycled jeans shredded cotton can. I am doing a complete renovation of my house right now and i ve chosen to insulate with roxul comfort batts. In some instances the polyethylene when taped and sealed also acts as the air control layer within the assembly.