What is the thickness of drywall commonly recommended for ceilings and walls that require additional fire resistance?

The recommended thickness of 5/8 inch for drywall used in ceilings and walls that require additional fire resistance is based on its ability to provide enhanced structural integrity and fire containment. This thickness is commonly referred to as "Type X" drywall, which is specifically designed to meet fire code requirements. Type X drywall contains special additives that improve its fire resistance, making it suitable for areas where a higher level of safety is needed, such as in multi-family dwellings, commercial buildings, and other regulated spaces.

In general, while 1/2 inch drywall is typical for interior walls and ceilings where fire resistance is not as critical, the 5/8 inch option provides that extra layer of protection. Thicker drywall, such as 3/4 inch or 1 inch, is rarely used in standard construction applications due to weight and structural limitations, and they do not typically offer additional fire resistance beyond what 5/8 inch Type X provides. Hence, 5/8 inch is the industry standard for balancing effective fire resistance and practical application in these scenarios.