A residential building inspector is reviewing plans for a new single-family dwelling that includes an attached garage. What is the minimum fire-resistance rating required for the wall separating the garage from the dwelling unit?
- A1-hour fire-resistance rating
- B1/2-hour fire-resistance rating
- C2-hour fire-resistance rating
- DNo rating required if separated by a door
Show answer & explanationAnswer & explanation
Correct answer: A. 1-hour fire-resistance rating
According to IRC R302.6, the garage and dwelling unit shall be separated by not less than 1/2-inch gypsum board or equivalent applied to the garage side. However, the code also states that the walls shall be not less than 1-hour fire-resistance-rated when the garage is located beneath habitable rooms or when the garage is attached and the wall forms part of the dwelling unit. For typical attached garages, a 1-hour fire-resistance rating is required for the separation wall.
Why the other options are wrong
- B. While 1/2-inch gypsum board is specified on the garage side, the overall rating for the wall separating the garage from the dwelling is typically 1-hour, especially if habitable spaces are above or it's part of the dwelling unit envelope (IRC R302.6).
- C. This rating is typically for more severe fire separation requirements, not standard attached garages.
- D. This is incorrect; a fire rating is always required for separation.
Garage-Dwelling Fire Separation
Minimum fire-resistance rating required for walls, ceilings, and doors separating an attached garage from the dwelling unit.
- Protects occupants from garage fires.
- Specific materials and ratings apply.
- Critical for life safety.
Memory trick: To keep the dwelling safe from garage flames, a one-hour wall plays fire-resistance games.