Residential Building Inspector B1Wall Construction and Wall CoveringsMedium

An inspector is reviewing plans for a residential building with a garage located beneath habitable spaces. What is the minimum fire-resistance rating required for the separation between the garage and the habitable space above?

  1. A1/2-hour
  2. B1-hour
  3. C3/4-hour
  4. D2-hour
Show answer & explanation

Correct answer: B. 1-hour

According to IRC Table R302.6, a 1-hour fire-resistance-rated separation is required between a garage and habitable space located above it. This applies to both the floor assembly and any walls separating the spaces.

Why the other options are wrong

  • A. 1/2-hour separation is required for garage walls adjacent to habitable spaces, but not for spaces above.
  • C. This is not a standard fire-resistance rating for garage separations in residential construction.
  • D. 2-hour ratings are typically for more stringent commercial or multi-family applications, not standard residential garages.

Garage-Habitable Space Fire Separation

Code-required fire-resistance ratings for assemblies separating a garage from adjacent or overhead habitable spaces to prevent fire spread.

  • 1-hour rating for spaces above.
  • 1/2-hour rating for walls adjacent.
  • Ensures occupant safety in case of garage fire.

Memory trick: Garage below, one hour to go.

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