Rockwool Insulation Toronto
Non-combustible mineral wool insulation that withstands 1,177 degrees Celsius. Superior fire resistance, soundproofing, and thermal performance.
Licensed | Insured | CUFCA Certified | OBC Compliant | Free Estimates
What Is Rockwool Mineral Wool Insulation?
Rockwool is a premium insulation material manufactured from natural basalt rock and recycled steel slag. The raw materials are heated to approximately 1,500°C in a cupola furnace, then spun into fine fibres and compressed into dense batts, boards, or loose fill. This stone-based composition gives rockwool properties that synthetic insulation materials simply cannot match.
Unlike fiberglass, which melts at around 540°C, rockwool is completely non-combustible and withstands temperatures up to 1,177°C without igniting, melting, or producing toxic smoke. This makes it the insulation of choice for fire-rated wall assemblies, commercial fire barriers, and any application where fire safety is paramount.
Beyond fire resistance, rockwool delivers R-4.0 per inch of thermal insulation, superior soundproofing with a Noise Reduction Coefficient (NRC) of 1.0 or higher, and natural water repellency. It does not rot, support mould growth, or attract pests. These combined properties make rockwool one of the most versatile and durable insulation materials available.
Why Choose Rockwool?
Fire Resistant
Non-combustible, withstands 1,177°C. Class A fire rating. Does not produce toxic smoke or contribute to flame spread.
Soundproofing
NRC 1.0+ rating. Dense fibre structure absorbs sound across all frequencies. Ideal for party walls, home theatres, and bedrooms.
Thermal Performance
R-4.0 per inch, 25% higher than fiberglass batts. Maintains R-value in cold temperatures unlike some alternatives.
Water Repellent
Naturally hydrophobic. Repels water rather than absorbing it. Dries quickly if exposed to moisture. Does not support mould.
Rockwool Applications
Interior Partition Walls
Rockwool Safe'n'Sound is specifically designed for interior partition walls where sound control is the priority. Its dense fibre structure absorbs airborne noise between rooms, making it the industry standard for bedrooms, home offices, home theatres, and bathroom walls. It provides STC ratings of 45-52 depending on the wall assembly.
Product: Safe'n'Sound
Fire Separation Assemblies
For walls requiring fire ratings between attached garages and living spaces, party walls in townhouses, and commercial fire barriers, rockwool is the premier insulation choice. Its non-combustible nature contributes directly to the fire resistance of the wall assembly, often allowing thinner overall wall construction while meeting OBC fire rating requirements.
Related: Fireproofing services
Exterior Continuous Insulation
Rockwool ComfortBoard is a rigid mineral wool board designed for exterior continuous insulation. Applied over the structural sheathing, it eliminates thermal bridging through studs, dramatically improving the wall's overall R-value. It is vapour permeable, allowing walls to dry outward, and its non-combustible nature meets fire code requirements for exterior cladding.
Product: ComfortBoard
Exterior Wall Cavities
Rockwool ComfortBatt is a friction-fit batt designed for standard 2x4 and 2x6 wall cavities. Its semi-rigid structure holds its shape without staples or fasteners, filling the cavity completely. At R-15 for a 2x4 wall and R-23 for a 2x6 wall, it outperforms fiberglass batts by approximately 25%.
Product: ComfortBatt
Commercial & Industrial
In commercial buildings, rockwool is used for fire barrier systems, curtain wall insulation, roof assemblies, and mechanical insulation around pipes and ducts. Its ability to withstand extreme temperatures makes it essential in industrial applications near high-heat equipment and processes.
Related: Garage insulation
Basement Headers & Rim Joists
Rockwool batts cut to fit rim joist cavities provide a fire-resistant alternative to spray foam in this critical area. While spray foam offers a better air seal, rockwool is preferred in applications where non-combustible materials are required by code or where spray foam application is not feasible.
Often paired with caulking for air sealing
Rockwool vs Fiberglass Batts
| Property | Rockwool | Fiberglass Batts |
|---|---|---|
| R-Value (3.5" batt) | R-15 | R-11 to R-13 |
| Fire Rating | Non-combustible (1,177°C) | Melts at ~540°C |
| Sound Rating (NRC) | 1.0+ | 0.7-0.8 |
| Water Resistance | Hydrophobic (repels water) | Absorbs moisture, sags |
| Density | Higher (friction-fit, holds shape) | Lower (requires staples) |
| Cost | $1.50-$2.00/sq ft | $1.00-$1.50/sq ft |
While fiberglass costs less, rockwool's superior fire resistance, soundproofing, and durability make it the better long-term value for many applications. Our team helps you determine which material is right for each area of your project.
Professional Rockwool Installation
Rockwool batts are installed using a friction-fit method. The batts are manufactured slightly wider than standard stud cavities, so they press into place and hold themselves without staples, nails, or adhesive. This ensures full contact with the cavity surfaces, eliminating air gaps that would reduce insulation performance.
For fire separation assemblies, proper installation is critical. Every cavity must be completely filled with no gaps or voids. Penetrations through the wall (electrical boxes, plumbing, HVAC) must be properly sealed with fire-rated caulk or putty pads. The drywall on the fire-rated side must be continuous and properly taped and finished.
Our installers are trained in both the thermal and fire-resistance requirements of rockwool installations. We ensure every project meets OBC requirements for fire rating, thermal performance, and vapour control. As fireproofing specialists, we understand the critical details that make fire-rated assemblies perform as designed.
Rockwool Product Lines
Safe'n'Sound
Interior partition walls. Optimized for sound absorption. Available for 2x4 and 2x6 wood and steel stud walls.
ComfortBatt
Exterior and interior walls. Thermal insulation with fire resistance. R-15 (2x4) and R-23 (2x6).
ComfortBoard
Rigid exterior continuous insulation. Eliminates thermal bridging. Available in various thicknesses.
AFB (Acoustic Fire Batt)
Commercial fire-rated assemblies. Used in steel stud partitions for STC and fire rating compliance.
Frequently Asked Questions
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