Floor Joist Cantilever Design

At the line of the cantilever support wall.

Floor joist cantilever design.

Similar to joists beams can cantilever up to one fourth their backspan. The ontario building code cantilevered floor joists 9 23 9 9. Many building departments limit joist cantilevers to 24 maximum. Element in the storey below in which case blocking is required by clause 7 1 2 1 of nzs 3604 2011 and figure 7 2.

Cantilevered floor joists 1 floor joists supporting roof loads shall not be cantilevered more than 400 mm beyond their supports where 38 mm by 184 mm joists are used and not more than 600 mm beyond their supports where 38 mm by 235 mm or larger joists are used. 2 the cantilevered portions referred to in sentence 1 shall not. 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. Cantilevers parallel to joist direction in this situation while the open web joist stops at an exterior bearing a 2x extension from it extends beyond the bearing to become the cantilever joist.

See section r301 2 2 2 5 item 1 for additional limitations on cantilevered floor joists for detached one and two family dwellings in seismic design category d 0 d 1 or d 2 and townhouses in seismic design category c d 0 d 1 or d 2. You must use at least five framing nails to attach the rim joist to the ends of your joists. A full depth rim joist shall be provided at the unsupported end of the cantilever joists. Design software will dictate specific framing practices but for our purposes here general approaches to cantilever installation will be discussed.

Branz recommends that all cantilevered joists have continuous blocking.