Mineral wool batts are about 25 percent more expensive than fiberglass, however, with an R-value of 4.0 per inch. Did you ...

Be aware, though, that you may have to special-order mineral wool batts. We used Roxul r value insulation batts. Mineral wool ...

This hybrid system combines high-density thermal insulation with compressible glass mineral fiber insulation ... sound solution to achieve roof U-values as low as 0.10 W/m²/K.