ComfortBoard, CavityRock, and CurtainRock Mineral Wool Board Insulation

Credit: Roxul Inc.

What makes this product green?

  • Reduces heating and cooling loads
  • Avoids hazardous ingredients
  • Pre-consumer recycled content


Roxul manufactures rigid and semi-rigid mineral wool board insulation for both commercial and residential applications. ComfortBoard, designed for applications over exterior 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 produced in the Milton, Ontario plant with a minimum 75% pre-consumer recycled content, primarily iron ore slag. The residential version, ComfortBoard IS, has a density of 8.0 pcf, while the commercial product, ComfortBoard CIS, has a density of 11 pcf. Roxul’s CavityRock is designed for cavity wallWall assembly constructed of two wythes of masonry bonded with wall ties and separated by an air cavity, which is sometimes filled with insulation. applications and provides drainage along with fire resistance. CurtainRock is made specifically for fire-rated curtain wall systems. According to the company, both retain thermal resistance when damp and are available faced or unfaced in different thicknesses and densities. The R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. ranges from 4.0 to 4.2 per inch. These products are produced with a urea-extended phenol formaldehydeChemical found in many building products; most binders used for manufactured wood products are formaldehyde compounds. Reclassified by the United Nations International Agency for Research on Cancer (IARC) in 2004 as a “known human carcinogen." binderGlue used in manufactured wood products, such as medium-density fiberboard (MDF), particleboard, and engineered lumber. Some binders are made with formaldehyde. See urea-formaldehyde binder and methyl diisocyanate (MDI) binder. , though heat processing during production drives off most of the formaldehyde, resulting in extremely low emissions.

Additional Info

Product Attributes

  • Pharos:
  • Pre-Consumer Content : 75 %

Manufacturer Information

Roxul Inc.
420 Bronte St., Unit 105
Milton, ON L9T 0H9
Phone: 905-878-8474
Fax: 905-878-8077
Toll-free: 800-265-6878

Listed in: Board Insulation


Dec 4, 2017 3:16 PM ET

Edited Dec 4, 2017 3:18 PM ET.

Response to Pioneer Builders
by Martin Holladay

Q. "Can any stone wool product be used for below-grade purposes?"

A. No, only the denser (semi-rigid) types of mineral wool are suitable for insulating the exterior of a foundation wall.

Remember, you shouldn't use any insulation product in a way that isn't recommended by the insulation manufacturer -- so when in doubt, contact the insulation manufacturer and ask whether the manufacturer supports your intended use of their product.

Dec 4, 2017 3:09 PM ET

Can any stone wool product be
by PioneerBuilders

Can any stone wool product be used for below grade purposes? Eg up against below grade concrete