Title 24 Cool Roof Requirements
Sacramento sits in California Climate Zone 12, and Title 24 Part 6 sets cool-roof requirements for low-slope re-roofing. This is why commercial flat roofs here are white, and it is checked at inspection.
The prescriptive values
For low-slope non-residential roofs, the prescriptive path calls for an aged solar reflectance of at least 0.20 and a thermal emittance of at least 0.75 — or alternatively a Solar Reflectance Index of at least 16.
The values that count are the aged ones rated by the Cool Roof Rating Council, not the initial figures on a marketing sheet. Membranes lose reflectance as they weather, and the rating accounts for that.
What this means in practice
- White TPO and white PVC meet the prescriptive values without special measures
- Dark mod-bit or built-up cap sheets generally do not, and need a reflective cap sheet or a coating
- The product's CRRC rating number belongs in your closeout documents
- There is also a performance compliance path, where a non-compliant roof is offset by other efficiency measures — that takes energy modelling and a signed compliance form
The 2025 edition
California updates Part 6 on a three-year cycle. The 2025 edition takes effect for permits applied for on or after 1 January 2026, so a project permitted in late 2025 and a project permitted in early 2026 can be held to different requirements.
Because the exact requirement depends on your building's occupancy, roof area and the scope of the re-roof, we confirm the applicable edition and section against the permit before specifying a product rather than assuming.
Common questions
Does Title 24 apply to a residential flat roof?
Residential requirements differ from non-residential ones and depend on the climate zone and the scope of work. Sacramento is Climate Zone 12 either way; the applicable section is confirmed at permit.
Does a roof repair trigger cool-roof requirements?
Requirements generally attach to re-roofing and alterations rather than minor repair, with area thresholds involved. Which category your project falls into is established with the building department before the work is specified.