Florida implemented a new prescriptive R-20 unvented attic on July 1, 2025. The standards for the unvented attic were passed as part of Florida HB 267 (2024). The new requirements for the R-20 unvented attic are:
Section 7. Effective July 1, 2025, section 553.9065, 718 Florida Statutes, is created to read:
553.9065 Thermal efficiency standards for unvented attic 720 and unvented enclosed rafter assemblies.
(1) Unvented attic and unvented enclosed rafter assemblies that are insulated and air sealed with a minimum of R-20 air impermeable insulation meet the requirements of sections R402 of the Florida Building Code, 8th Edition (2023), Energy Conservation, if all of the following apply:
- (a) The building has a blower door test result of less than 3 ACH50.
- (b) The building has a positive input ventilation system or a balanced or hybrid whole-house mechanical ventilation system.
- (c) If the insulation is installed below the roof deck and 732 the exposed portion of roof rafters is not already covered by the R-20 air-impermeable insulation, the exposed portion of the roof rafters is insulated by a minimum of R-3 air-impermeable insulation unless directly covered by a finished ceiling. Roof rafters are not required to be covered by a minimum of R-3 air impermeable insulation if continuous insulation is installed above the roof deck.
- (d) All indoor heating, cooling, and ventilation equipment and ductwork is inside the building thermal envelope.
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