Is CavityRock fire rated?

Yes. It is non-combustible mineral wool with a melting point around 2150°F, suited to fire-resistant wall assemblies.

What R-value does the 6 in board give?

R-8.6 per board at 6 in thickness. R-value holds up because the wool does not absorb moisture.

Where can it be installed?

Exterior cavity walls and exterior wall stud cavities, mainly in commercial construction. It is unfaced, so plan for weather detailing.

How much area does a package cover?

64 sq ft per package. Check your wall area before ordering, since packs cannot be split.

Is it good for soundproofing?

It adds acoustic absorption in wall cavities, which helps with outside noise, but pair it with proper sealing for the best result.

Is $2,440 a good price?

Only one new price is listed, $2,440.00 at MyHackerTech as of November 7, 2026, so there is no recent range to compare it against. Compare per-square-foot cost with other mineral wool board sellers.

Where is the Rockwool CavityRock Mineral Wool 24" x 48" cheapest?

At MyHackerTech, for $2,440.00, as of our latest check.

Where can I buy the Rockwool CavityRock Mineral Wool 24" x 48"?

2 stores we checked sell it, including MyHackerTech, Arbor.

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Rockwool CavityRock Mineral Wool 24" x 48"

Best price now

$2,440.00at MyHackerTechObserved at 1:43 PM

Prices are checked against each store and labelled with when.

Visit MyHackerTech

Rockwool CavityRock Mineral Wool 24" x 48"

Best price now

$2,440.00at MyHackerTechObserved at 1:43 PM

Prices are checked against each store and labelled with when.

Visit MyHackerTech

Ask our agent about this product

It checks today's price at every store, compares the alternatives and answers in about a minute.

Our take on the Rockwool CavityRock Mineral Wool 24" x 48"

Rockwool CavityRock is a rigid, unfaced mineral wool board for exterior cavity walls and wall stud cavities, mainly in commercial builds. It combines thermal insulation (R-8.6 at 6 in) with non-combustible fire performance and acoustic absorption, and it resists moisture without losing R-value. The only new price listed is $2,440.00 at MyHackerTech as of November 7, 2026, with no other new-store prices to compare against.

Best forCommercial exterior cavity wall insulationBuildings that need non-combustible insulationProjects where sound control mattersDamp or wet-exposure wall assemblies

Pros

Non-combustible mineral wool with high fire resistance
R-8.6 at 6 in thickness
Moisture resistant; keeps insulating value when wet
Absorbs sound as well as heat
Unfaced rigid board installs cleanly in cavities
Made from natural and recycled materials, CFC- and HCFC-free

Cons

High-density rigid board is heavy and awkward to handle
6 in thickness eats cavity depth
Unfaced board needs careful detailing at joints
Sold in 64 sq ft packs, so small jobs leave leftovers
Only one new price listed, so value is hard to judge

Rockwool CavityRock Mineral Wool 24" x 48" prices at every store

MyHackerTechNew
In stock
$2,440.00Observed at 1:43 PM
Visit MyHackerTech

Also available at

ArborCheck price at Arbor

Rockwool CavityRock Mineral Wool 24" x 48" price history

Lowest price we've seen: $2,158.14 on Nov 7 at Arbor. Tracked across 4 stores since Nov 7.

What reviewers say

Buyers of CavityRock boards generally report solid fire and moisture performance and easier handling than expected for a dense board. Complaints center on weight, cutting effort and the cost of full packs.

What people mention

Fire performancePraisedOwners value the non-combustible rating for commercial wall assemblies.
MoisturePraisedReviewers say it keeps insulating when the cavity gets damp.
WeightCriticisedThe dense boards are tiring to carry and install, especially overhead.
CuttingMixedIt cuts cleanly with a saw but throws dust.
PriceCriticisedBuyers find full packs expensive when only part is needed.

Specifications

Form: Board
Product Type: Rigid Foam Board, Batt
Insulation Type: Thermal
Insulated Plasterboard: No
Fire Rating Class: Non-combustible, Fire resistant
Material Type: Mineral Wool
Facing: Un-Faced

Questions and answers

Is CavityRock fire rated?: Yes. It is non-combustible mineral wool with a melting point around 2150°F, suited to fire-resistant wall assemblies.
What R-value does the 6 in board give?: R-8.6 per board at 6 in thickness. R-value holds up because the wool does not absorb moisture.
Where can it be installed?: Exterior cavity walls and exterior wall stud cavities, mainly in commercial construction. It is unfaced, so plan for weather detailing.
How much area does a package cover?: 64 sq ft per package. Check your wall area before ordering, since packs cannot be split.
Is it good for soundproofing?: It adds acoustic absorption in wall cavities, which helps with outside noise, but pair it with proper sealing for the best result.
Is $2,440 a good price?: Only one new price is listed, $2,440.00 at MyHackerTech as of November 7, 2026, so there is no recent range to compare it against. Compare per-square-foot cost with other mineral wool board sellers.
Where is the Rockwool CavityRock Mineral Wool 24" x 48" cheapest?: At MyHackerTech, for $2,440.00, as of our latest check.
Where can I buy the Rockwool CavityRock Mineral Wool 24" x 48"?: 2 stores we checked sell it, including MyHackerTech, Arbor.