Rockwool Vapor Barrier Attic

Drywall with taped seams.

Rockwool vapor barrier attic.

Rock wool insulation for the same wall cost about 1 06 per square foot. For more information on the need for air barriers behind metal fireplaces visit this useful web page from the u s. Rockwool insulation is moisture resistant yet vapor permeable. I d personally seal the attic and not use any petro based papers or non inert vapor retarders barrier materials or house wraps like most foams wraps that don t work since they lack cfm or high perm nor are chemically stable.

If it becomes damp or wet the insulation when dried out will maintain the original performance characteristics. Rockwool insulation is moisture resistant yet vapor permeable. Fiberglass insulation for a 2 6 wall costs between 57 cents and 72 cents per square foot. Any water that contacts the outer surface will drain and not be absorbed into the body of the insulation.

The best air barrier material in this case would be 1 2 in. Despite the fact these two barrier systems are neither the same nor interchangeable there is sometimes confusion in the industry as a single material is often used for both functions. Interior moisture that cannot be eliminated must be controlled by employing an effective air barrier and vapor retarder barrier. In the event the insulation becomes damp or wet the insulation when thoroughly dried will maintain the original performance characteristics.

Rockwool stone wool insulation does not wick water which means that any bulk water that contacts the outer surface will drain and not be absorbed into the body of the insulation. I design my envelop with two materials that mate well mw and 100 wood period. While there is no need for a vapor barrier you certainly need an air barrier in this location.