What is the MINIMUM wallboard thickness for the walls separating a house and garage? (garage side)

• A. 1/4 inch
• B. 1/2 inch
• C. 3/4 inch
• D. 5/8 inch

Answer: (B)

Fire separation between a living space and an attached garage is required to slow the spread of a fire. Gypsum board is used to create that barrier, and the minimum thickness for the drywall on the garage side is 1/2 inch. This thickness is the standard baseline for interior walls and provides the necessary protection when installed properly with the wall framing. Thinner material, like 1/4 inch, would not meet the typical fire-safety requirement, while thicker options such as 3/4 inch or 5/8 inch are used only if a higher fire-resistance rating is needed or specified, but the minimum required thickness for the garage side is 1/2 inch.