Massachusetts Construction Supervisor License (CSL) Practice Test

What is the maximum allowed cantilever span for a 2x8 floor joist supporting an exterior balcony with a ground snow load of 50 psf?

1. 30 inches

2. 34 inches

3. 36 inches

4. 42 inches

The correct answer is: 34 inches

To determine the maximum allowed cantilever span for a 2x8 floor joist supporting an exterior balcony, it's important to refer to the building codes and span tables that provide guidelines for different materials and loads. The National Design Specification (NDS) for Wood Construction and the American Wood Council's span tables serve as a foundation in this context. For a 2x8 southern pine floor joist with a ground snow load of 50 pounds per square foot (psf), the maximum cantilever span is typically limited based on the allowable load and specific wood species. In general, a 2x8 joist can safely cantilever approximately 34 inches under the specified loading conditions, since larger spans may compromise the structural integrity and safety of the balcony. This limit ensures appropriate deflection and strength under the expected load, playing a critical role in preventing collapse and providing long-term durability in construction. Therefore, the correct answer reflects the adherence to these construction standards, ensuring that the structure remains safe for use while complying with the guidelines established by the Massachusetts building codes.