Construction Supervisor License Practice Exam

Which of the following fastenings are to be used when fastening 5/8 inch plywood to rafters?

1. 8d, 6 " o.c. direct edges, 12 " o.c. intermediate

2. 6d, 6 " o.c. direct edges, 8 " o.c. intermediate

3. 8d, 4 " o.c. direct edges, 12 " o.c. intermediate

4. 6d, 4 " o.c. direct edges, 8 " o.c. intermediate

The correct answer is: 8d, 6 " o.c. direct edges, 12 " o.c. intermediate

When fastening 5/8 inch plywood to rafters, using 8d nails spaced at 6 inches on center (o.c.) at the edges and 12 inches o.c. for intermediate supports is essential for ensuring a strong and stable connection. The choice of 8d nails is appropriate for this application because they are of sufficient length to penetrate through the plywood and securely engage with the rafters beneath, providing the necessary holding power. The spacing of 6 inches on center along the edges helps to distribute the load effectively and reduces the likelihood of edge splitting, which is crucial when dealing with the thinner plywood material. Additionally, the 12 inches on center spacing for the intermediate sections promotes adequate support while allowing for some flexibility, accommodating minor expansions and contractions that may occur due to temperature and humidity changes. This fastening method aligns with common building codes and industry standards, ensuring that the structure remains sound and compliant. In contrast, other options may have inappropriate nail sizes or spacing that do not adhere to recommended practices, potentially compromising the integrity of the plywood installation.