above deck insulation Bison board

The Thermal Break: Eliminating Rafter R-Value Degradation with Above-Deck Continuous Insulation Under Steep-Slope Shingles

• September 24, 2026
• admin

In high-performance building envelope engineering across peninsular India, thermal performance calculations often look impressive on paper: structural rafter bays are specified with thick resin-bonded stone wool batts offering rated thermal resistance values of R-19 to R-30. Yet, during the pre-monsoon summer months—when roof surface temperatures on dark architectural shingles routinely reach 65°C to 75°C—conditioned indoor …