Mineral Wool Board Insulation
Mineral wool insulation board is a high-density rigid panel designed primarily for continuous exterior insulation applications. When installed on the outside of wall sheathing, it breaks thermal bridging through studs and provides a continuous thermal layer across the entire wall area. Unlike rigid foam boards, mineral wool board is non-combustible and does not require a thermal barrier on the exterior. It is also vapor-permeable, allowing wall assemblies to dry to the outside, which is an important consideration in moisture-sensitive climates. The boards are typically available in 2-foot by 4-foot panels in thicknesses from 1 inch to 4 inches, providing R-4.3 per inch of thickness.
Mineral Wool Board Specifications
Best Applications for Mineral Wool Board
Mineral Wool Board is recommended for the following building components. Each application link shows the specific R-value requirements by climate zone and how Mineral Wool Board compares against other insulation options for that component.
Thickness Required by Climate Zone
The table below shows the thickness of Mineral Wool Board needed to achieve the DOE recommended R-value for each building component in every climate zone. Cells showing "N/R" indicate that insulation is not required for that component in that zone. Use this table to quickly determine how much Mineral Wool Board you need for your specific zone and application.
| Zone | Attic | Wall Cavity | Wall Cont. | Floor | Basement | Crawlspace | Cathedral | Garage |
|---|---|---|---|---|---|---|---|---|
| Zone 1 | 7" | 3" | N/R | 3" | N/R | N/R | 5.1" | 4.4" |
| Zone 2 | 8.8" | 3" | N/R | 3" | N/R | N/R | 5.1" | 4.4" |
| Zone 3 | 8.8" | 3" | N/R | 4.4" | 1.2" | 1.2" | 7" | 4.4" |
| Zone 4 | 11.4" | 3" | 1.2" | 5.8" | 2.3" | 2.3" | 8.8" | 7" |
| Zone 5 | 11.4" | 3" | 1.2" | 5.8" | 2.3" | 2.3" | 8.8" | 7" |
| Zone 6 | 14" | 3" | 2.3" | 5.8" | 3.5" | 2.3" | 11.4" | 8.8" |
| Zone 7 | 14" | 3" | 2.3" | 5.8" | 3.5" | 2.3" | 11.4" | 8.8" |
| Zone 8 | 14" | 3" | 3.5" | 5.8" | 4.4" | 2.3" | 11.4" | 8.8" |
Cost Estimates by Climate Zone (per 1,000 sq ft)
Material cost estimates for Mineral Wool Board at the DOE recommended R-value for each climate zone and component. These are material costs only and do not include labor. Professional installation typically adds 30-50% to the material cost shown below.
| Zone | Attic | Wall Cavity | Wall Cont. | Floor | Basement |
|---|---|---|---|---|---|
| Zone 1 | $7,500 | $3,250 | N/R | $3,250 | N/R |
| Zone 2 | $9,500 | $3,250 | N/R | $3,250 | N/R |
| Zone 3 | $9,500 | $3,250 | N/R | $4,750 | $1,250 |
| Zone 4 | $12,250 | $3,250 | $1,250 | $6,250 | $2,500 |
| Zone 5 | $12,250 | $3,250 | $1,250 | $6,250 | $2,500 |
| Zone 6 | $15,000 | $3,250 | $2,500 | $6,250 | $3,750 |
| Zone 7 | $15,000 | $3,250 | $2,500 | $6,250 | $3,750 |
| Zone 8 | $15,000 | $3,250 | $3,750 | $6,250 | $4,750 |
Advantages and Limitations
Every insulation type has trade-offs that affect its suitability for different applications. Understanding these trade-offs helps you select the right insulation for your specific project requirements, budget, and installation constraints.
Advantages of Mineral Wool Board
- Suitable for DIY installation, reducing labor costs
- Excellent moisture resistance for wet or below-grade applications
- Non-combustible — no thermal barrier required in most applications
- Superior fire resistance provides additional safety margin
- Well-suited for: Wall Continuous (Exterior), Basement Wall
Limitations of Mineral Wool Board
Compare Other Insulation Types
Browse specifications and cost analysis for other insulation materials to find the best option for your project.