What is the required gypsum thickness for garage walls adjacent to non-habitable areas?

In residential building codes, the thickness of gypsum board (drywall) used for specific areas such as garage walls adjacent to non-habitable spaces is primarily determined by fire resistance and safety requirements. The correct requirement for this application is 1/2 inch thickness. This standard is generally prescribed because it provides adequate fire protection while being cost-effective and manageable for building contractors.

Gypsum board of this thickness is typically suited for separating garage spaces from living areas or non-habitable areas, as it helps to prevent the spread of fire and smoke. In contrast, thicker options like 5/8 inch or higher would be more appropriate for walls that require superior fire resistance, such as those separating different occupancy types or in commercial settings. Thus, using 1/2 inch gypsum around garage walls is both compliant with the building codes and practical for the intended use.