4x8 sheet format for high-productivity wall coverage
Key features
About R-6.3 at 1.5 in. using R-4.2/in at 75 °F per TDS
Published compressive strength note per ASTM C165 on TDS for attachment discussions
Technical specifications
| R-Value | 6.3 |
|---|---|
| Thickness | 1.5 in |
| Width | 48.0 in |
| Length | 96.0 in |
| Coverage | 32.0 sq ft/pack |
| Material | Rigid stone wool (non-structural continuous insulation / CI board) |
| Fire rating | Noncombustible per ASTM E136; Flame Spread 0 / Smoke Developed 0 per ASTM E84 on USA Comfortboard 80 TDS (07-2025). |
| Sound rating | NRC 0.90 and SAA 0.93 at 1.5 in. per ASTM C423 on USA Comfortboard 80 TDS (07-2025). |
| Density | 8 lb/ft³ actual density per ASTM C303 on USA Comfortboard 80 TDS (07-2025). |
| Thermal conductivity | R-4.2 per inch at 75 °F; RSI 0.74 per 25.4 mm at 24 °C per ASTM C518 (C177) on USA TDS. |
| Framing width | Continuous insulation (not stud-spacing specific) |
| Construction type | Wood or steel frame (exterior CI; non-structural) |
| Application area | Exterior continuous insulation and compatible foundation or slab edge uses per manufacturer / ICC-ES scope. |
Product details
When the facade schedule rewards fewer panel joints, 4 ft by 8 ft Comfortboard 80 sheets at 1-1/2 in. cover more wall per piece than 2x4 modules, provided the crew has laydown, lifting, and edge protection.
Thermal resistance follows R-4.2 per inch at 75 °F, about R-6.3 for the board layer; whole-wall compliance still requires framing factor, cavity insulation, and other CI layers.
The product remains non-structural: integrate structural sheathing as designed, then place Comfortboard outboard with furring, clips, or long fasteners per engineering.
Fire and smoke indices mirror other thicknesses on the sheet.
Acoustically, cite the 1.5 in. row: NRC 0.90 and SAA 0.93 in the ASTM C423 table.
Manufacturer testing cites low sorption and fungi resistance per the TDS; execution still depends on drained cavities and flashing.
Submittals should include https://www.rockwool.com/siteassets/o2-rockwool/documentation/technical-data-sheets/residential/comfortboard-80-non-structural-sheathing-continuous-insulation-techdata.pdf Issued 07-2025 or newer superseding issue.
Documents & certifications
Technical data sheet
Manufacturer-tested R-value, coverage, fire notes, and handling—use for submittals, RFIs, and field QA.
Download PDF (opens in new tab)Certifications & compliance
ASTM C612 Type IVB, CAN/ULC S702 Type I, ASTM E136 noncombustible, CAN/ULC S114 non-combustible, ASTM E84 / CAN/ULC S102 flame spread 0 / smoke developed 0 (Note 1 Class A per IBC on TDS), ASTM C303 actual density 8 lb/ft³, ASTM C518 R-4.2 per inch at 75 °F (RSI 0.74 per 25.4 mm at 24 °C), ICC-ES ESR-3773 on USA TDS (Issued 07-2025)
Frequently asked questions
How much area per sheet?
How much area per sheet?
A 48 by 96 in. sheet is 32 sq ft before cuts; verify bundle counts and waste factors on purchase orders.
Can this replace plywood sheathing?
Can this replace plywood sheathing?
No. Comfortboard 80 does not carry structural sheathing duties. Keep structural panels per the engineer of record.
What about panel joints?
What about panel joints?
Treat joints per ROCKWOOL installation literature and the project air barrier strategy.
Stone wool CI versus foam in fires?
Stone wool CI versus foam in fires?
Comfortboard 80 is documented as noncombustible with 0/0 flame/smoke indices on the USA TDS; compare to foam plastics using AHJ requirements and assembly listings.