CSLB C-39 Roofing ContractorFlashing, Ventilation and InsulationMedium
Under California's Title 24 Energy Code, a builder is installing a steep-slope residential roof and wants to meet the prescriptive cool roof requirement using an aged solar reflectance rating. What is the minimum aged solar reflectance value the roofing product must meet?
- A0.10
- B0.20
- C0.63
- D0.40
Show answer & explanationAnswer & explanation
Correct answer: B. 0.20
Title 24's prescriptive cool roof requirement for steep-slope residential roofs sets a minimum aged solar reflectance of 0.20 (along with a minimum thermal emittance of 0.75, or an SRI of 16), which reduces heat gain compared to standard dark roofing materials.
Why the other options are wrong
- A. Too low to meet the code minimum for steep-slope cool roofs.
- C. This exceeds the steep-slope prescriptive requirement significantly.
- D. This value applies to some low-slope roof requirements, not the steep-slope alternative.
Title 24 Steep-Slope Cool Roof
Title 24 requires steep-slope residential roofing to meet a minimum aged solar reflectance of 0.20 and thermal emittance of 0.75 for prescriptive compliance.
- Aged solar reflectance minimum: 0.20
- Thermal emittance minimum: 0.75
- Alternative: SRI of 16
Memory trick: Two-tenths reflects enough sun to pass steep-slope Title 24.