Posted on January 6, 2017 by Martin Holladay, GBA Advisor
Fibrous insulation materials like mineral wool do not stop air flow. Unlike rigid foam (which is a pretty good air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both., as long as the seams between panels are taped), mineral wool can only slow down air flow, not stop it.
So what happens when builders install mineral wool insulation on the exterior side of wall sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen.
? Is the thermal performance of the mineral wool degraded by wind?