Do I Need Title 24 for a Roof Replacement?
Only if more than half the roof surface is replaced, and then only where your climate zone calls for it. The roofing requirements of Section 150.2(b)1I begin above that 50 percent line. The practical question is whether your zone, slope and share of roof put you under the cool roof rules before the roofer orders shingles.
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Check the half-way mark carefully
The Standards say "more than 50 percent" of the roof, and this includes laying a new surface over the old one. The compliance manual's worked answer says "50 percent or more". If your job sits at exactly half, ask the department which reading it applies, or plan for the stricter one.
Zone and slope decide the rest
A steep-sloped re-roof needs a cool roof product only in climate zones 4 and 8 to 15, so zones 1, 2, 3, 5, 6, 7 and 16 have no such requirement. A low-sloped roof needs one in zones 4 and 6 to 15, so none is needed in zones 1, 2, 3, 5 and 16, though low-sloped roofs in zones 1, 2 and 16 still carry the insulation rule. A house with both slopes meets each rule on its own portion. Several exceptions let a steep roof skip the product, such as an R-38 ceiling or an attic radiant barrier; they are set out on the re-roofing page.
Two cases that are easy to miss
- Change of use. The manual's example is a Victorian converted to an office that needs a new shake roof. The single-family roof section does not apply, because the occupancy is now nonresidential and the roof rules of Section 141.0 apply instead; see commercial roof replacement.
- Solar roofing. On an integrated photovoltaic roofing product only the active panel area is exempt. The inactive filler pieces must still meet the requirements, and the product must be rated by the Cool Roof Rating Council.
What to ask the roofer
For the product's CRRC-rated aged solar reflectance and thermal emittance, because the code is written against those aged figures and an unrated product takes low defaults. Replacing wood shakes with shingles is still a replacement, not a repair, and the product choices are on cool roof shingles. Whether a permit is needed is the department's decision. Our residential reports cover re-roofs, and your climate zone is the first thing to look up.
Common Title 24 Questions
- What is Title 24?
- Do I need a Title 24 report?
- How much does a Title 24 report cost?
- How long does a Title 24 report take?
- What is included in a Title 24 report?
- What plans do I need to upload?
Frequently Asked Questions
The cool roof and roof insulation requirements apply only where more than 50 percent of the roof is replaced, according to Section 150.2(b)1I. The manual words it as 50 percent or more.
No. Section 150.2(b)1I sets cool roof requirements for steep-sloped roofs in zones 4 and 8 to 15 and low-sloped roofs in zones 4 and 6 to 15.
Explore Roofs
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- Are Your Shingles Title 24 Compliant?
- Remodel With Roof and Attic Insulation Changes: Title 24 Checklist
- Coating a Flat Roof: Title 24 Rules for Liquid-Applied Roof Coatings
- Solar Roof Tiles and Shingles: Do They Need a Cool Roof Rating?
View all Roofs guides → · Windows and Building Envelope · Title 24 guide