Question 20
Domain 3: Floor Construction and Supporting FramingWhat is the maximum cantilever length for a standard 2x10 floor joist per the IRC?
Correct answer: D
Explanation
The IRC does not give a single fixed maximum cantilever length for a 2x10 floor joist. Cantilever limits depend on the joist span, species, grade, spacing, and loading conditions, so the allowable overhang must be taken from the span tables or engineered design rather than a universal number.
Why each option is right or wrong
A. 12 inches
B. 24 inches (the depth of the joist)
C. 36 inches
D. It depends on the joist span and loading conditions
IRC Section R502.3.3 governs joist cantilevers and does not assign a single fixed overhang for a nominal 2x10; the allowable projection is limited by the joist span and the loading conditions shown in the span tables. Under the IRC span-table approach in Section R502.3.1, the permitted cantilever is derived from the specific joist species, grade, spacing, and design load, so the maximum length cannot be stated as one universal number for all 2x10 floor joists.