California Title 24 Part 6 mandates that any residential or commercial roof replacement exceeding 50% of the roof surface (or 300+ sq ft) must meet strict Cool Roof standards in designated Climate Zones. In high-desert Climate Zone 14 (Lancaster/Palmdale) and Climate Zone 9 (Los Angeles/Gardena), steep-slope residential roofs require a minimum aged Solar Reflectance Index (SRI) of 16 to 20, while low-slope commercial roofs require an aged SRI of 75+.
Key Technical Takeaways
- Title 24 applies to all permitted re-roofs exceeding 500 sq ft or 50% of total roof area.
- Cool roofs use solar-reflective granules and pigments to reflect infrared radiation while appearing in rich, dark architectural colors.
- City building departments verify CRRC (Cool Roof Rating Council) product labels before final permit sign-off.
- Installing cool roof materials lowers attic temperatures by up to 30°F, reducing home air conditioning bills.
What Is the California Title 24 Cool Roof Mandate?
California Energy Code (Title 24, Part 6) is designed to reduce greenhouse gas emissions and electrical grid strain during peak summer afternoons. In hot inland climate zones, conventional asphalt roofs absorb up to 90% of solar energy, turning attics into 150°F heat ovens. Title 24 mandates that newly installed roofing products reflect a substantial percentage of solar heat back into the atmosphere (Solar Reflectance) and quickly emit any heat that is absorbed (Thermal Emittance).
Understanding Solar Reflectance Index (SRI)
Solar Reflectance Index (SRI) is a composite scale from 0 to 100+ that measures a material's ability to stay cool in the sun. Black asphalt has an SRI of ~0; standard white single-ply has an SRI of ~100. Under Title 24: 1) Steep-Slope Residential (> 2:12 pitch) must achieve a minimum 3-year aged SRI of 16 to 20 (or initial solar reflectance of 0.20), and 2) Low-Slope Commercial (<= 2:12 pitch) must achieve an aged SRI of 75 (or solar reflectance of 0.63 and thermal emittance of 0.75).
Do Cool Roofs Have to Be White?
No! Many homeowners assume complying with Title 24 means they must install a white roof on their home. Modern manufacturing technology incorporates specialized ceramic-coated granules that reflect invisible infrared light (which causes heat) while absorbing visible light (which creates color). Brands like GAF Timberline HDZ RS (Reflector Series) and Owens Corning Duration Cool offer rich architectural colors—charcoal, weathered wood, barkwood, and slate—that fully comply with Title 24.
Permitting and Verification: CF-1R Forms
When APR Roofing pulls a building permit for your roof in Lancaster, Palmdale, or Los Angeles County, we submit the official California Energy Commission CF-1R-ENV-01 compliance document. The city building inspector matches the CRRC product rating number on the shingle bundles during final inspection, ensuring 100% legal compliance.
- Never allow an unpermitted contractor to install non-compliant dark shingles; city inspectors can issue stop-work orders or require complete roof tear-off at homeowner expense.
- Verify that cool roof shingle bundles display the official Cool Roof Rating Council (CRRC) seal.
Repair vs. Replace Decision Matrix
- •Repairs constitute less than 50% of the roof area or under 300-500 square feet, which are exempt from Title 24 trigger mandates in most jurisdictions.
- •Existing non-compliant shingles can be patched with matching materials for minor storm damage.
- •Complete re-roofing requires mandatory Title 24 compliance and municipal permit sign-off.
- •Homeowner wants to capture energy efficiency rebates and reduce summer utility bills.
Frequently Asked Questions
Does Title 24 apply to tile roofs in California?
Yes. Concrete and clay tiles installed in designated climate zones must feature cool roof color coatings or meet alternative attic ventilation / radiant barrier insulation exemptions specified in CEC Title 24 Section 150.1.
Are Title 24 cool shingles more expensive than regular shingles?
Cool roof architectural shingles typically cost only $5 to $15 more per roofing square than non-rated shingles, a minor difference quickly recouped in reduced cooling electricity costs.
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