Cool Roofs and Title 24 in LA: What Homeowners Actually Need to Know

California Title 24 Part 6 requires cool-roof materials on most re-roofs — and LA enforces it. Here's what actually applies to a residential re-roof in 2026.

When Title 24 triggers

• Low-slope (≤ 2:12) residential re-roofs: cool-roof compliance required.
• Steep-slope re-roofs: cool-roof aged solar reflectance ≥ 0.20 in Climate Zones 10–15 (covers LA).
• Repairs under 50% of the roof: exempt.
• Non-visible flat sections behind parapets: often exempt (verify with permit tech).

What it costs you

A cool-roof shingle upgrade (e.g., GAF Timberline HDZ Reflector) adds roughly $200–$500 to a typical LA re-roof. TPO and PVC flat systems are cool-roof compliant by default.

What it saves you

LADWP data shows cool-roofs cut summer AC load by 10–20% on single-story homes with attic space above conditioned rooms — most noticeable in the Valley and inland cities like Pasadena, Glendale, and Pomona.