TL;DR

Do not assume a cool roof is required on every San Diego reroof. Most coastal steep-slope homes sit in Climate Zone 7. Inland parcels can sit in Climate Zone 10. Low-slope work can follow a different package than steep-slope. Confirm the climate zone and the slope category with the authority having jurisdiction (AHJ) and with the Title 24 documents attached to the bid. Look the zone up on the California Energy Commission climate zone map.

The bid has to name a listed product with published solar reflectance and thermal emittance, not “a light color.” Whether this job is a qualifying reroof or a repair is a question for the contractor and the AHJ before anyone orders material. Top Pro Roofing SD refers. We do not install. Call (760) 750-5557.

What Title 24 is asking for on a San Diego reroof

Title 24, Part 6 is California’s Building Energy Efficiency Standards. On a qualifying reroof, the new covering has to meet the cool-roof metrics for your climate zone and roof slope, using the values in the current Energy Code cycle. Those tables change. We will not invent SRI cutoffs or code table numbers here. The contractor pulling the permit should cite the listed product and the AHJ should accept it.

San Diego County is not one zone. A La Jolla parcel and a Ramona parcel can sit in different CEC climate zones. Zone 7 vs Zone 10 changes which package you are in. Look it up for the address. Do not guess from a blog.

If the AHJ treats the job as a qualifying reroof, asphalt shingles, tile, and low-slope membranes have to play by the cool-roof rules that apply to that slope and zone. Products that show up in the CEC Cool Roof Rating Council / listed directory (homeowners often see CRRC, ENERGY STAR, or similar labels on the wrapper) are the easy way to prove the numbers. Ask for the product ID on the bid, not a color chip.

Permit process and IB-123 notes for City of San Diego reroofs: roof permit process.

What makes a roof a cool roof

Color helps. It is not the whole test.

Solar reflectance (SR) is how much sunlight bounces off the surface. Higher means less heat into the covering.

Thermal emittance (TE) is how well the surface dumps the heat it did absorb.

Together they keep attic and deck temperatures down compared with a dark, low-emittance surface. That is the energy point of the standard. Exact minimums are in the current Title 24 documents for your slope and zone. Confirm them with the AHJ and the listed spec sheet.

Low-slope roofs (commonly described as about 2:12 and under) are treated more strictly than steep-slope because they see more direct sun. Confirm the slope category on the permit, not from a photo.

Cool roof options by covering

Asphalt shingles. Makers sell granule formulas that meet cool-roof listings, including some darker-looking lines. When you plan an asphalt shingle replacement, the Title 24 question is “which listed product,” not “any architectural shingle.” UV and granule wear in this climate: what deteriorates asphalt shingles in San Diego.

Tile. Clay and concrete, especially lighter bodies or listed coatings, can meet the metrics. Glaze and color still have to match the listing, not only HOA taste. Confirm the tile ID the same way you would a shingle.

Low-slope / flat. White TPO is a common listed choice. Other membranes can qualify if they are in the directory. Coatings on an existing membrane are a different path than a full reroof. For membrane work see flat roof TPO and flat roof replacement.

Underlayment choice (felt vs synthetic) is not a substitute for a listed cool covering. See underlayment types.

Energy savings: what we will and will not claim

San Diego has long sun seasons. A darker, low-reflectance roof runs hotter than a listed cool roof on the same attic. How much that cuts your SDG&E cooling bill depends on insulation, ducts, windows, shade, and how you run the HVAC. We will not invent a 10-15% savings figure or a fixed attic-temperature drop.

Ask the matched roofer and, if you want a number, an energy auditor to talk about this house. Title 24 compliance is a permit condition. Bill savings are a separate, house-specific result.

Rebates and tax credits

Utility rebates open and close. SDG&E is the place to check current residential programs, not a blog. State and federal incentives change. The former federal residential energy credit that applied to some building envelope work ended for installs after December 31, 2025. Do not plan a 2026 reroof around that credit.

Confirm any rebate before materials are ordered. Eligibility can require a specific listed product and a closed permit.

How a reroof meets the current energy rules

A qualifying reroof is a chance to put a listed covering on the house and to fix ventilation and flashing that were never part of the old assembly. The installing contractor (not Top Pro Roofing SD) pulls the permit, schedules inspections, and shows the AHJ the product paperwork.

You should see on the bid:

  • Climate zone they are using (7 vs 10 vs other), matching the parcel
  • Slope category (steep vs low)
  • Product name and listing ID
  • Who confirms exceptions, if any, with the AHJ

Then roof replacement is the project path.

FAQ

What is Title 24 roofing in California?

Cool-roof and related energy rules inside Title 24, Part 6. They set listed reflectance and emittance (and related metrics) for new construction and for reroofs that meet the replacement trigger. The point is lower cooling load. The current CEC standards are the source, not a contractor’s memory of an old cycle.

Do I need a cool roof in San Diego?

Confirm climate zone and slope with the AHJ and the Title 24 documents on the bid. Most coastal steep-slope homes are Zone 7. Zone 10 and low-slope assemblies can differ. This page does not default to yes. The permit inspector and the approved plans decide.

What is the exact Title 24 cool roof number?

It depends on slope, zone, and code cycle. Ask the contractor for the listed product and the AHJ for acceptance. Do not treat a blog SRI as the current table.

Repairs vs full replacement?

Title 24 uses a replacement-area test in the current Energy Code. Read that test on the Title 24 forms for this bid. Patching a small storm area can stay on matching existing product when the AHJ treats it as repair. Confirm scope in writing so nobody treats a large field replacement as a patch.

Are there exemptions?

Some historic, overlay, or solar-coverage situations get special handling. They are narrow. Roof-mounted solar does not automatically erase the cool-roof rule. Ask the contractor pulling the permit to confirm any exception with the AHJ before you order a non-listed covering.

When to call

If you are reroofing, ask the matched C-39 to put climate zone, slope category, and a listed product ID on the bid, then confirm those lines with the AHJ. Call (760) 750-5557. We connect San Diego County homeowners with vetted CSLB-licensed roofers. We do not pull permits or install.

For flat membrane repair, see flat roof repair.