Attached garages: airtight + insulated common wall + door, no HVAC supply or return in garage, vent garage to outdoors

Description

Where an attached garage exists, Indoor airPLUS requires: (1) common wall between garage + dwelling sealed airtight with gypsum board on garage side per IRC R302.6 PLUS additional air-sealing (caulked top + bottom plate, no recessed lights, gasketed door); (2) NO HVAC supply or return air vents in the garage; (3) garage mechanically vented to outdoors (or, for older homes, an operable window). Doors between garage + dwelling must be self-closing and gasketed.

Why this exists

Garages contain exhaust fumes (cars), gasoline storage, paints, fertilizers, etc. The IRC requires fire-rated separation; airPLUS adds air-tight separation to keep those contaminants from being drawn into the dwelling on negative pressure. Architects should specify the gasketed garage door + self-closer in the door schedule.

Categories

Source

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

• Cathedral ceilings: gable-end wall stud must extend to roofline (no hinge at top plate) · HUD RSDG §5.6.2
• In high-wind zones, soffits need solid blocking at exterior walls · HUD RSDG §5.6.5
• Sill-plate anchor bolts: 1/2" diameter @ 6 ft on-center, max 12 inches from corners/splices · HUD RSDG §7.4.3
• Ramps over 6 inches rise must have handrails on both sides · HUD FHA Design Manual Chapter Two §2.8
• Floor surface vertical changes: 1/4 inch max vertical; 1/2 inch max with 1:2 bevel · HUD FHA Design Manual Chapter Four §4.2