KEY PROVISIONS
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The insulation requirements for roof alterations apply to all roof replacements and recovers regardless of whether existing insulation is located above or below the roof deck.
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The prescriptive minimum requirements for roof alterations are:
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R-17 or R-23 (depending on climate zone) with the use of continuous insulation (ci) only; or
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U-0.042 or U-0.037 (depending on climate zone) if the insulation is a combination of continuous and cavity insulation. Assemblies insulated with cavity insulation must have a minimum R-10ci installed above the roof deck.
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There are two exceptions that include important backstops:
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Roof Recovers: Recovers are not required to meet the full R-17/23 (or U-0.037/0.042) requirements if at least R-10ci of new insulation is installed above the roof deck.
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Equipment Curbs and Flashing Heights: The maximum amount of insulation (up to the prescriptive requirement) or R-10ci, whichever is greater, must be installed where flashing heights associated with HVAC equipment curbs present limiting conditions.
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USEFUL LINKS
- The California Energy Commission’s web-based tool for locating the Climate Zone applicable to a specific project can be accessed here.
- The California 2022 Energy Code, Reference Appendices (including JA4), Climate Zone Maps, and the 2022 Multifamily and Nonresidential Compliance Manual can be accessed here.
- Energy Code Ace tools, training, and resources (including fact sheets) can be accessed here.
