What thickness of type X gypsum is required on a garage ceiling below a living space?

The correct choice is 5/8 inch gypsum because it meets the fire-resistance requirements for ceilings in garages that are beneath living spaces. In many building codes, including those commonly accepted in Minnesota, type X gypsum board is specified for use in fire-rated assemblies, particularly in situations where a garage is adjacent to or below living areas. The 5/8 inch thickness of type X gypsum provides enhanced fire resistance compared to thinner alternatives, making it suitable for this application.

This thickness is essential to ensure that the structural integrity of the living space above is maintained in the event of a fire within the garage, providing additional time for occupants to evacuate and for firefighters to respond. It is tailored to fulfill both safety regulations and fire code requirements, thus protecting lives and property.