Is ROCKWOOL AFB fire rated?

Yes. It is noncombustible per ASTM E136, scores 0 for flame spread and smoke developed on ASTM E84, and carries UL BZJZ and ULC BZJZC fire-resistance design classifications for rated partitions.

How much area does a bag cover?

The listing states 80 sq ft per bag at 3 in thickness, from 24 in x 48 in batts. The spec sheet's 64 sq ft figure refers to 4 in thickness, so check which thickness you are ordering.

How well does it block sound?

It has an NRC of 1.10 at 3 in, which is high absorption. That helps control echo and noise inside rooms; for stopping sound passing between rooms, pair it with proper wall assembly and sealing.

Can I use it in a house?

It is intended for commercial new construction, mainly fire-rated partitions and plant walls. It can go in residential stud walls, but the unfaced batts need drywall or another covering.

Does it need a vapor barrier?

AFB has low moisture sorption and does not promote mold, but it is unfaced. In exterior walls, follow the assembly design for a vapor retarder; it is not a substitute for one.

Is $89.38 a good price?

Only one store, The Spray Market, lists it new at $89.38 as of November 7, 2026, so there is no recent range to compare. Check the coverage per bag against other stone wool batts before deciding.

Where is the ROCKWOOL AFB Acoustical Fire Batts cheapest?

At The Spray Market, for $89.38, as of our latest check.

ROCKWOOL AFB Acoustical Fire Batts

Best price now

$89.38at The Spray MarketObserved at 12:28 PM

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Our take on the ROCKWOOL AFB Acoustical Fire Batts

ROCKWOOL AFB is an unfaced stone wool batt for interior steel and wood stud walls and floors, sold in 3 in thick, 24 in x 48 in pieces. It is noncombustible (ASTM E136) with flame spread 0 and smoke developed 0, and it absorbs sound well: NRC 1.10 at 3 in. It is aimed at fire-rated commercial partitions rather than finished living space. The only new price found is $89.38 at The Spray Market as of November 7, 2026, with no other store to compare against.