When installing cementitious backer units (CBUs), which type of nails should not be used?

When installing cementitious backer units (CBUs), drywall nails should not be used due to their lack of appropriate strength and corrosion resistance. Drywall nails are designed for securing lightweight drywall to wooden studs and are not adequate for the heavier and potentially more hydrophilic cementitious backer units. They may not provide the structural integrity necessary for holding CBUs securely in place, which can lead to sagging or detachment over time, especially in wet areas.

In contrast, regular nails, galvanized nails, and finish nails might have more appropriate applications depending on the specific installation requirements. Galvanized nails, for example, offer resistance to rust, making them suitable for moisture-prone areas, which is essential when working with materials like CBUs that may be exposed to water. Regular nails can be used in some scenarios, provided they are installed correctly and are of sufficient strength to handle the load. Meanwhile, finish nails, while being more aesthetic for trim work, also have adequate strength for securing thinner materials. However, they would not be the first choice for CBUs due to their slender nature and design purpose.

Choosing the right fastening method is crucial to ensure that the cementitious backer units remain securely anchored and perform effectively over time.