Residential Building Inspector B1Wall Construction and Wall CoveringsEasy
A residential building inspector is observing the installation of interior wall coverings in a newly constructed dwelling. The builder plans to use gypsum board as the interior finish directly on wood studs. Which of the following is the minimum thickness required for gypsum board applied to studs spaced 24 inches on center?
- A5/8 inch
- B1/4 inch
- C3/8 inch
- D1/2 inch
Show answer & explanationAnswer & explanation
Correct answer: D. 1/2 inch
For gypsum board applied to studs spaced 24 inches on center, the minimum required thickness is 1/2 inch to ensure adequate rigidity and prevent sagging. This is a standard requirement found in residential building codes.
Why the other options are wrong
- A. 5/8 inch gypsum board is often used for fire-rated assemblies or for enhanced rigidity, but it is not the minimum requirement for 24-inch stud spacing.
- B. 1/4 inch gypsum board is typically used for curved surfaces or as a base layer, not as a primary wall finish on 24-inch centers.
- C. 3/8 inch gypsum board is generally suitable for studs spaced 16 inches on center, but not for 24-inch spacing.
Gypsum Board Minimum Thickness (Interior Walls)
The smallest allowable thickness for gypsum board when used as an interior wall finish, based on stud spacing.
- Thickness depends on stud spacing.
- Thicker board provides more rigidity.
- Code specifies minimums for safety and performance.
Memory trick: Gypsum's thickness depends on how wide the studs are spaced.