Description
Rockwool Comfortbatt R-30: More R-Value in Less Space
A standard fiberglass R-30 batt is about 10 inches thick. Rockwool Comfortbatt R-30 gets there in about 7¼ inches because stone wool is denser. That matters in vaulted and cathedral ceilings, 2×8 rafter bays, and the low-slope attics common in mid-century LA homes, where there simply isn’t room for a thicker batt and compressing one throws away R-value.
Specifications
| Brand | Rockwool |
|---|---|
| Product line | Comfortbatt |
| R-value | R-30 |
| Thickness | About 7¼ in. |
| Batt size | 23 x 47 in. (for 24 in. on-center framing) |
| Coverage | About 30 sq ft per bag |
| Facing | Unfaced |
| Fire | Non-combustible (ASTM E136); flame spread 0 (ASTM E84) |
Where to Use It
- Vaulted and cathedral ceilings with 2×8 or 2×10 rafters (leave the required vent space above).
- Low-clearance attics where 10-inch batts won’t fit.
- Attics in wildfire-prone areas, for non-combustible insulation.
How Many Bags?
At about 30 sq ft per bag, a 600 sq ft vaulted ceiling needs 600 ÷ 30 = 20 bags, plus about 5% for cuts: 21 bags.
Buy It or Have It Installed
Order Comfortbatt R-30 here, or let our licensed crew (CSLB #1139733) do the work. See all Rockwool insulation, or Comfortbatt R-38 for deeper attic floors.
Rockwool Comfortbatt R-30 Unfaced Stone Wool FAQ
- How thick is Rockwool R-30?
- About 7¼ inches, compared with about 10 inches for a fiberglass R-30 batt.
- What framing does the 23-inch batt fit?
- Framing at 24 inches on center. The batt is slightly oversized so it friction-fits between the members.
