What material is specified as a draft stopping material in the code?

Draft stopping is a critical component in residential construction, particularly in attics and spaces between floors where the potential for air movement through gaps could lead to heat loss or compromise energy efficiency. The North Carolina Residential Code specifies materials that can effectively serve as draft stopping to limit the passage of air.

The combination of 1/2 inch gypsum and 3/8 inch plywood provides the necessary fire-resistant properties and structural integrity required for effective draft stopping. Gypsum board is non-combustible and provides a barrier that prevents flames from spreading, making it a suitable choice in these applications. Plywood, especially when specified at 3/8 inch, offers sufficient strength and can be used in conjunction with gypsum to further enhance the draft stopping capability.

This selection meets code requirements for material thickness, fire rating, and performance, ensuring that both draft and fire protection standards are upheld. Other materials listed may not meet the same level of safety or effectiveness. For instance, while 1/2 inch plywood could potentially offer some draft stopping, it does not provide the same fire resistance as gypsum board. Therefore, the combination of the specified materials in the correct answer aligns with the intent and requirements of the code for ensuring safety and efficiency in residential construction.