40 Hour Property and Building Inspection Practice Test

If spaced 16 inches apart, what is a typical maximum span for common joists?

1. 8 feet

2. 12 feet

3. 16 feet

4. 20 feet

The correct answer is: 16 feet

In residential construction, common joists spaced 16 inches apart typically have a maximum span of about 16 feet. This span allows for appropriate support and load distribution for materials such as flooring and ceiling assemblies, ensuring structural integrity and safety. Different factors, such as the size of the joists, the type of wood, and the loads they are expected to carry, can affect the effective span. When considering joists, the 16-foot span is generally accepted as a standard for 2x10 or 2x12 lumber, assuming normal residential loading conditions. Using spans beyond this limit can lead to issues such as sagging or structural failure, making it essential for builders and inspectors to adhere to these guidelines to ensure a safe living environment. The other options present spans that either exceed the standard limits or are less than what is typically anticipated for common applications, which is why they are not as suitable as the correct choice.