What does the NRCA recommend for fastening a wood roofing system?

The National Roofing Contractors Association (NRCA) emphasizes the importance of determining the proper length of fasteners based on the total thickness of all roofing materials being fastened. This practice ensures that the fasteners penetrate the underlying structure sufficiently for a secure hold, while also preventing damage to the materials being installed. By considering the combined thickness, roofing professionals can select fasteners that provide adequate support and durability, which is essential for the longevity of the roofing system.

The other options do not align with best practices; for instance, using the same length fasteners for all applications neglects the specific requirements of different materials and layers. Likewise, relying solely on longer fasteners does not guarantee a better hold if they do not match the thickness of the materials involved. Finally, making a selection based solely on the material type ignores the critical factor of layer thickness, which can lead to insufficient fastening and potential roofing failure.