CodeMandatory
Garage HVAC duct prohibition
IRC R302.5.2Description
Ducts that pass through a garage must be 26-gauge or thicker steel, with no openings in the garage. HVAC ducts cannot use the garage as a return-air plenum.
Why this exists
CO and other combustion byproducts in a garage must not infiltrate dwelling air.
Categories
Life safetyVentilation
Source
ICCno manifest entry
International Residential Code (2024)
Section: R302.5.2
Published 2024-01-01 · last verified 2026-05-09
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Related directives
- Garage / dwelling fire separation · IRC R302.6
- Natural light in habitable rooms · IRC R303.1
- Habitable space minimum ceiling height · IRC R305.1
- Egress window net opening dimensions · IRC R310.2
- Stair riser, tread, and headroom · IRC R311.7
Last reviewed 2026-05-09.