California Residential Inspector Practice Exam

How many layers of gypsum board are typically required to be applied to ceilings with adhesive?

1. One layer

2. Two layers

3. Three layers

4. Four layers

The correct answer is: Two layers

In residential construction, when gypsum board is applied to ceilings using adhesive, it is standard practice to apply two layers. This approach not only helps in achieving the desired fire resistance rating but also enhances sound control and structural rigidity. The first layer is typically attached directly to the ceiling joists, while the second layer is applied over the first, usually staggered to minimize joint alignment. This layering technique reinforces the ceiling, helping to prevent sagging and improving overall durability. The use of two layers with adhesive also promotes a more seamless finish and can aid in reducing potential cracks over time. Applying only one layer would not provide the same level of performance in terms of fire safety and sound insulation, making it insufficient for most residential applications. More than two layers, while occasionally utilized in specialized circumstances, is not standard for typical residential ceilings and may introduce unnecessary complexity and weight.