In This Guide
Title 24 Part 6: Energy Code for Roofing
Title 24 is the California Building Standards Code, and Part 6 (the California Energy Code) is the section that most directly affects roof replacement projects. California's energy code is the most stringent in the nation and is updated on a three-year cycle. The current 2022 code cycle took effect January 1, 2023. For homeowners, the key roofing requirements involve cool roof compliance, attic insulation, and radiant barrier installation.
What Title 24 Requires for Re-Roofing
When you replace your roof in California, Title 24 Part 6 requires compliance with cool roof material standards (solar reflectance and thermal emittance minimums based on your climate zone), attic insulation upgrades if the existing insulation is below current minimum R-values, and radiant barrier installation in applicable climate zones when the roof deck is exposed during re-roofing.
The scope of these requirements depends on the extent of the re-roofing work. A complete tear-off to the deck triggers the most comprehensive requirements because it exposes the attic for insulation and radiant barrier work. An overlay (second layer) triggers fewer requirements but still requires cool roof compliance for the new surface material. Your contractor must complete a Certificate of Compliance (CF-1R for residential) documenting that the project meets all applicable Title 24 requirements.
Solar Reflectance and Thermal Emittance Minimums
Title 24 specifies minimum values for two properties that determine how much heat a roof absorbs and re-radiates:
- Solar Reflectance (SR): The fraction of solar radiation reflected by the roof surface. Higher values mean less heat absorption. Measured on a 0-to-1 scale.
- Thermal Emittance (TE): The ability of the roof surface to release absorbed heat. Higher values mean the roof cools faster. Measured on a 0-to-1 scale.
- Solar Reflectance Index (SRI): A combined metric incorporating both SR and TE. Used as an alternative compliance path.
For steep-slope residential roofing in applicable climate zones, the 2022 minimums are an aged solar reflectance of 0.20 and thermal emittance of 0.75, or an SRI of at least 16. For low-slope roofing (flat roofs), the minimums are significantly higher: an aged solar reflectance of 0.63 and thermal emittance of 0.75. Products are rated by the Cool Roof Rating Council (CRRC), and compliant products are listed in the CRRC Rated Products Directory.
Cool Roof Requirements by Climate Zone
California divides the state into 16 climate zones, and cool roof requirements vary by zone. Understanding which zone your property falls in determines whether you need cool-rated roofing materials and what the specific performance minimums are.
| Climate Zones | Region | Steep-Slope Cool Roof | Low-Slope Cool Roof |
|---|---|---|---|
| 1-9 | Coastal, Northern CA, Bay Area | Not required (residential) | Required |
| 10-15 | Inland valleys, Southern CA, Desert | Required (SR 0.20, TE 0.75) | Required |
| 16 | High mountain (above 5,000 ft) | Not required (residential) | Required |
Which Materials Meet Cool Roof Standards?
Metal roofing in light colors (white, light gray, light tan) typically meets cool roof standards without modification. Concrete and clay tile in light colors also comply. For asphalt shingles, you need specifically labeled “cool roof” or “cool color” products that use reflective granules — standard dark-colored shingles do not meet the SR 0.20 minimum. TPO and PVC membranes for flat roofs meet cool roof requirements in white. Modified bitumen and built-up roofing need a reflective coating to comply. Always verify that the specific product and color you select is listed in the CRRC Rated Products Directory.
Performance Credits and Trade-Offs
Title 24 allows performance trade-offs through the Alternative Calculation Method (ACM). If you cannot or prefer not to install cool roofing (for example, if the color options for cool-rated shingles do not match your aesthetic preference), you can compensate by exceeding the code in other areas such as additional attic insulation, higher-efficiency HVAC, or radiant barrier installation. This calculation must be performed by a certified energy consultant using approved software (CBECC-Res) and documented on the CF-1R compliance form. The performance trade-off path adds $500 to $1,500 in energy consulting fees but provides flexibility in material selection.
Chapter 7A: Fire-Resistant Construction
Chapter 7A of the California Building Code governs fire-resistant construction in Wildland-Urban Interface (WUI) zones and applies to all new construction and re-roofing projects in designated Fire Hazard Severity Zones. This is separate from and in addition to Title 24 energy requirements.
Key Roofing Requirements
- Class A fire-rated roofing assembly — the complete system (material, underlayment, and deck) must be tested and rated Class A per ASTM E108 or UL 790
- Ember-resistant vents — all ridge, off-ridge, soffit, and gable vents must resist ember intrusion per ASTM E2886
- Non-combustible gutters with gutter covers or screens to prevent debris accumulation
- 36-inch metal valley flashing under all roof valleys
- Non-combustible bird stops at tile eaves to prevent ember entry under tiles
- Enclosed eaves and soffits with non-combustible or ignition-resistant materials
Where Chapter 7A Applies
Chapter 7A applies in State Responsibility Areas (SRA) classified as moderate, high, or very high fire hazard severity, and in Local Responsibility Areas (LRA) classified as Very High Fire Hazard Severity Zones (VHFHSZ). AB 3074 (effective 2024) expanded the LRA requirement significantly. Check the CAL FIRE FHSZ Viewer at osfm.fire.ca.gov to determine your property's classification. For a comprehensive guide to WUI zone roofing, see our Wildfire Roofing California Guide.
Seismic Considerations for Roofing
California is seismically active across the entire state, and roof weight and attachment directly affect how a structure performs during an earthquake. While seismic codes do not prohibit any specific roofing material, they impose requirements that affect material choice and installation cost.
Weight by Material
- Metal Standing Seam100-150 lbs/sq
- Asphalt Shingles200-350 lbs/sq
- Composite Slate300-400 lbs/sq
- Concrete Tile900-1,100 lbs/sq
- Clay Tile800-1,000 lbs/sq
When Structural Upgrades Are Required
If your re-roofing project increases the roof load by more than 10 percent (for example, switching from asphalt shingles to concrete tile), the building department will require an engineering analysis of the existing roof framing. This analysis determines whether the rafters, ridge beam, wall top plates, and foundation can support the additional weight under both gravity and seismic loading. Structural reinforcement, if needed, typically costs $3,000 to $10,000 and involves adding sister rafters, upgrading connectors, and in some cases reinforcing wall framing.
Roof Diaphragm Requirements
California seismic codes require roof sheathing to function as a structural diaphragm, transferring lateral earthquake forces to the walls and foundation. This requires specific nail patterns (typically 6-inch edge nailing and 12-inch field nailing for standard zones, with tighter spacing in high-seismic zones), minimum sheathing thickness (typically 15/32-inch plywood or 7/16-inch OSB), and approved edge clips or blocking between panels. During a tear-off, the contractor and inspector will evaluate the existing sheathing and attachment for compliance.
CSLB C-39 Licensing Requirements
California law requires that any contractor performing roofing work costing $500 or more (including labor and materials) hold a valid license from the Contractors State License Board (CSLB). The specific license classification for roofing is C-39 (Roofing Contractor). Understanding CSLB licensing protects you from unlicensed operators and ensures you have recourse if something goes wrong.
What the C-39 License Requires
To obtain and maintain a C-39 license, a contractor must pass both a trade examination and a law and business examination, demonstrate a minimum of 4 years of journeyman-level roofing experience, maintain a $25,000 contractor license bond (protects consumers against license law violations), carry workers compensation insurance if they have employees, and complete continuing education requirements. The license is renewed every 2 years and is subject to disciplinary action for code violations, consumer complaints, and failure to maintain required insurance.
How to Verify a License
Always verify a contractor's license before signing a contract. Use the CSLB license lookup tool at cslb.ca.gov to confirm:
- License status (active vs. expired, suspended, or revoked)
- License classification (should include C-39 for roofing)
- Bond status (should show an active $25,000 bond)
- Workers compensation status (should be active if they have employees)
- Complaint history and any disciplinary actions
- License issue date (indicates experience level)
B License vs. C-39 License
A contractor holding a B (General Building) license can legally perform roofing work as part of a larger construction project (such as a home addition or remodel). However, for a standalone roof replacement project, a C-39 specialist license indicates specific roofing expertise and trade examination. Both license types provide the same consumer protections (bond, insurance requirements, CSLB oversight). When comparing roofing quotes, note the contractor's license classification — a C-39 holder focuses specifically on roofing, while a B holder is a generalist.
Maximum Roofing Layers and Tear-Off Rules
California follows the International Building Code (IBC) and International Residential Code (IRC) standards for maximum roofing layers, with additional state-specific requirements for WUI zones.
Asphalt Shingles
Maximum of two layers permitted. If the existing roof has two layers, a complete tear-off to the deck is mandatory. Most contractors recommend tear-off even when an overlay is technically permitted because it allows deck inspection, proper underlayment installation, and better long-term performance.
In WUI zones, tear-off is often required by the building department regardless of the number of existing layers, to ensure the complete assembly meets Chapter 7A.
Tile, Metal, and Other Materials
Only one layer is permitted for tile, metal, slate, composite, and other non-shingle materials. You cannot install tile over existing tile or metal over existing metal. A complete tear-off is always required when switching material types (for example, from shingles to tile or from tile to metal).
Tear-off costs in California typically run $1.00 to $2.50 per square foot, or $2,000 to $5,000 for a typical 2,000 square foot roof, including disposal fees.
Permit Process for California Roofing
A building permit is required for roof replacement in virtually all California jurisdictions. The permit ensures that the project complies with structural, energy, fire, and accessibility codes. Your roofing contractor typically handles the permit application and inspections, but you should understand the process.
Step-by-Step Permit Process
- Application submission: The contractor submits an application to the local building department with the proposed roofing assembly details (material type, underlayment, deck condition), project valuation, and contractor license information.
- Plan review: The building department reviews the application for code compliance. For standard re-roofing, this is often an over-the-counter (same-day) process. For WUI zone projects or material changes requiring structural review, plan check can take 2 to 6 weeks.
- Permit issuance and fee payment: Permit fees vary by jurisdiction and project value, typically ranging from $200 to $800 for residential re-roofing.
- Deck/underlayment inspection: After tear-off and before the roofing material is installed, the inspector verifies deck condition, nail pattern, underlayment type and installation, flashing, and drip edge.
- Final inspection: After the roofing material is installed, the inspector verifies material compliance, proper installation per manufacturer specifications, flashing and penetration details, and vent compliance (especially in WUI zones).
- Certificate of completion: Upon passing final inspection, the building department issues a certificate. This document is important for warranty claims, insurance documentation, and future property sales.
What Happens Without a Permit?
Working without a permit in California is a misdemeanor and can result in fines, required removal and reinstallation of the roofing work, and voiding of both the contractor warranty and manufacturer warranty. When you sell your home, unpermitted work must be disclosed and often requires retroactive permitting (which may involve removal for inspection). Insurance claims may also be denied for unpermitted roofing work. Always confirm that your contractor pulls a proper permit before starting work.
CALGreen Standards for Roofing
CALGreen (California Green Building Standards Code, Title 24 Part 11) is the state's mandatory green building code. While most of CALGreen's provisions target new construction, several requirements apply to roofing replacement projects.
Construction Waste Diversion
CALGreen requires that at least 65 percent of construction and demolition waste be diverted from landfills through recycling or reuse. For roofing projects, this primarily applies to the tear-off material. Asphalt shingles are recyclable into road asphalt (hot mix asphalt pavement), and California has a growing network of shingle recycling facilities. Metal roofing is highly recyclable. Concrete and clay tile can be crushed for aggregate. Your contractor must document waste diversion through receipts from recycling facilities as part of the project closeout. Most established California roofing contractors have recycling relationships in place to meet this requirement.
Stormwater and Material Containment
During roofing work, CALGreen requires erosion control measures and containment of roofing materials to prevent debris and contaminants from entering storm drains. This includes tarping or netting around the work area to catch loose materials, covering exposed soil, and proper disposal of roofing adhesives, sealants, and cleaning solutions. Your contractor should have a site-specific pollution prevention plan, particularly for projects near waterways or in areas with stormwater runoff concerns.
Low-Emitting Materials
Adhesives, sealants, and coatings used in roofing installation must comply with SCAQMD Rule 1168 VOC (Volatile Organic Compound) limits. This affects the roofing cement, lap sealant, and primer products used during installation. All major roofing product manufacturers now offer compliant formulations, so this is generally not a limitation, but your contractor should be using approved products.
Solar-Ready Requirements
Since 2020, California has required solar photovoltaic systems on all new single-family homes. While this mandate does not directly apply to re-roofing projects, a roof replacement is the ideal time to plan for solar integration, and some jurisdictions offer incentives for combined roof-and-solar projects.
Why Coordinate Roofing and Solar
Installing solar panels on a new roof is significantly more cost-effective than retrofitting later. You avoid the cost of removing and reinstalling panels ($1,500 to $3,000) when the roof eventually needs replacement. The solar mounting system can be engineered as part of the roof design, ensuring proper waterproofing and structural integration. The new roof warranty remains intact since penetrations are made during original installation rather than retrofitted afterward. Some California jurisdictions and utilities offer expedited permitting for combined roof-and-solar projects. If you are planning to add solar within the next 5 years, coordinate the projects now.
Solar-Compatible Roofing Materials
Not all roofing materials are equally compatible with solar panel mounting. Metal standing seam is the most solar-friendly material because panels attach with non-penetrating clamps that grip the seam ridges, eliminating roof penetrations entirely. Asphalt shingles are compatible with standard rail-mount systems using flashed lag bolts. Concrete and clay tile require specialized tile hooks that replace individual tiles at attachment points, adding complexity and cost. Flat roofs (TPO, PVC) use ballasted or non-penetrating rack systems. When choosing your roofing material, discuss solar compatibility with your contractor if solar is in your future plans.
Get a Code-Compliant Roofing Estimate
Enter your California address to get satellite-measured roof data and instant estimates from pre-vetted, CSLB-licensed local contractors. No phone calls, no spam.
California Roofing Building Codes FAQ
What is Title 24 and how does it affect my California roof replacement?
Title 24 is the California Building Standards Code, with Part 6 (the Energy Code) being the section most relevant to roofing. For roof replacements, Title 24 Part 6 requires cool roofing materials that meet minimum solar reflectance and thermal emittance values based on your climate zone. As of the 2022 code cycle (effective January 2023), steep-slope roofs in climate zones 10 through 15 must have a minimum aged solar reflectance of 0.20 and thermal emittance of 0.75, or a Solar Reflectance Index (SRI) of at least 16. Low-slope (flat) roofs statewide must meet even higher reflectance requirements. Your contractor must specify compliant materials in the permit application, and the building inspector will verify compliance.
Do I need a permit to replace my roof in California?
Yes, California requires a building permit for roof replacement in virtually all jurisdictions. A roofing permit ensures the work complies with the California Building Code (structural, fire, and energy requirements), the California Residential Code, and local amendments. The permit process typically involves submitting a permit application with the proposed roofing assembly details, paying permit fees (typically $200 to $800 depending on the jurisdiction and project value), passing an inspection of the underlayment and deck before the roofing material is installed, and passing a final inspection after completion. In WUI zones, additional fire department review may be required. Working without a permit can result in fines, required removal of the work, and complications when selling or insuring your home.
What are California cool roof requirements by climate zone?
California's cool roof requirements vary by building type, roof slope, and climate zone. For residential steep-slope roofs, the 2022 Title 24 requires cool roof compliance in climate zones 10 through 15 (the hottest inland and Southern California zones). Climate zones 1 through 9 (coastal and Northern California) are exempt for steep-slope residential. For low-slope (flat) roofs, cool roof requirements apply statewide across all 16 climate zones. Non-residential buildings have stricter requirements that apply in more climate zones. The specific minimums are 0.20 aged solar reflectance and 0.75 thermal emittance for steep-slope, and 0.63 aged solar reflectance and 0.75 thermal emittance for low-slope. Materials meeting CRRC (Cool Roof Rating Council) standards are listed in the CRRC directory.
How many layers of roofing can I have on my California home?
California Building Code Section 1511.3 permits a maximum of two layers of asphalt shingle roofing on residential structures. If your roof already has two layers of shingles, a complete tear-off to the deck is required before the new roof can be installed. For tile, metal, and other non-shingle materials, only one layer is permitted (you cannot install a new tile roof over an existing tile roof). In practice, most California roofing contractors recommend a full tear-off even when a second layer is technically permitted, because exposing the deck allows inspection for rot, damage, and code-compliant underlayment installation. In WUI zones, tear-off is often required by the building department to ensure the complete roofing assembly meets Chapter 7A fire requirements.
What CSLB license does a California roofing contractor need?
California law requires roofing contractors to hold a valid Contractors State License Board (CSLB) license. For roofing-specific work, the required classification is C-39 (Roofing Contractor). A contractor with a B (General Building) license can also perform roofing work as part of a larger project but cannot advertise as a roofing specialist. The CSLB license ensures the contractor has passed trade and business exams, maintains a $25,000 contractor bond, carries workers compensation insurance (if they have employees), and is subject to CSLB regulatory oversight. You can verify any contractor license at cslb.ca.gov, which shows license status, bond status, workers compensation status, and complaint history. Never hire an unlicensed contractor for roofing work in California: the penalties include fines up to $5,000 and up to 6 months in jail for the contractor, and you lose access to the Contractors State License Board dispute resolution process.
What are the seismic requirements for roofing in California?
California's seismic requirements primarily affect roofing through weight restrictions and attachment standards. Heavy roofing materials like concrete tile (900 to 1,100 pounds per square) and clay tile (800 to 1,000 pounds per square) require structural verification to ensure the roof framing can handle both the dead load and the additional lateral forces generated during an earthquake. For re-roofing projects where the new material is significantly heavier than the existing material (for example, replacing asphalt shingles with concrete tile), an engineering analysis of the existing framing is typically required. The California Residential Code requires specific nail patterns and attachment methods for roof sheathing in high seismic zones to prevent diaphragm failure during earthquakes. Your building department will review the structural adequacy as part of the permit process.
What is CALGreen and how does it affect roofing?
CALGreen (California Green Building Standards Code, Title 24 Part 11) is the state mandatory green building code. For roofing, CALGreen requires construction waste management (at least 65 percent of roofing demolition waste must be diverted from landfill through recycling), stormwater management during construction (erosion control and material containment), and low-emitting materials for adhesives and sealants used in roofing installation. Most asphalt shingle tear-off material is recyclable into road asphalt, and California has a growing network of shingle recycling facilities. Your contractor must provide documentation of waste diversion as part of the project closeout. CALGreen also encourages but does not currently mandate cool roofing beyond what Title 24 Part 6 requires.
Are solar-ready requirements part of California roofing codes?
Yes. Since 2020, California has required all new single-family homes and many low-rise multifamily buildings to include solar photovoltaic systems under the 2019 Title 24 code cycle. While this mandate applies to new construction rather than re-roofing, it is relevant for homeowners planning a roof replacement because installing a new roof is the ideal time to add solar. The code also requires a "solar zone" of unshaded, south-facing roof area. If you are replacing your roof and considering solar panels, coordinate both projects: installing solar on a new roof is more cost-effective than retrofitting later, the roofing material warranty remains intact, and the solar mounting is engineered as part of the roof system. Some jurisdictions offer expedited permitting for combined roof-and-solar projects.