Attached two-car garage with a bedroom above it.

IRC Requirements (2018+):

Garage Ceiling (with habitable room above):

• Drywall: ½" minimum gypsum board (Type X not required by code, but recommended)
• Ceiling joists: Must support 1-hour fire rating
• Installation: All joints taped and finished per GA-216

Walls between garage and house (fire separation):

• Drywall: ½" minimum gypsum board on garage side only
• Fire rating: ½-hour fire wall (IRC Section R309.6.1)
• Coverage: Full height of wall, including around garage door openings
• Penetrations: All electrical boxes must be sealed, HVAC ducts require approved fire dampers

Key Details:

• Garage door area: Drywall extends to underside of garage door header
• Foundation wall: If garage is below grade, foundation walls also need ½" drywall
• Ceiling slope: If ceiling is sloped, drywall covers entire surface

Safety Note: While ½" regular drywall meets minimum code, Type X (fire-rated) drywall is strongly recommended for both applications, especially with a bedroom above. This provides better fire protection and may reduce insurance liability.

Bottom line: ½" gypsum board on garage ceiling and garage-side of shared walls. Type X is the safer choice.

Always check local amendments - some jurisdictions require 5/8" Type X throughout.

Garage Ceiling (under bedroom): 5/8" Type X gypsum board. IRC R302.6 / IBC 714.4.2: The garage–dwelling separation requires a 1-hour fire-resistance rating. A single layer of 5/8" Type X on the garage side of the ceiling assembly satisfies this (UL Design L501, etc.). Standard 1/2" does not.

Garage–House Common Walls: 5/8" Type X gypsum board on the garage side. IRC R302.6: Same 1-hour rating. One layer of 5/8" Type X on the garage face of the wall meets code. If the wall is load-bearing or you want rating from both sides, apply 5/8" Type X both faces.

Key details:

• Tape joints and coat fasteners; untreated joints = no rating.
• Extend board to the underside of the roof deck or install fireblocking at the top plate (R302.11).
• Penetrations (ducts, pipes, wires) must be firestopped per UL system or IRC R302.4.1.2.
• No 1/2" "fire-code" board—only 5/8" Type X (or proprietary 1/2" Type X if listed for 1-hr in that assembly).

Local amendments can require 5/8" Type X on both sides of the wall or on the bedroom ceiling too. Verify with your building department before hanging.