Decks.com. Deck Joist Cantilever Rules and Limits
30 May 2017 Learn what factors determine the maximum joist cantilever overhang that is allowed for a deck. The distance your joists can safely cantilever or overhang a drop beam is determined by the size of the joists, the wood type and grade of the lumber and the spacing between joists. Many building departments limit joist cantilevers to 24" maximums. joist to the ends of your joists. The American Wood Council states that cantilevers are limited to 1/4 the span of the joists.