Maximum Floor Joist Cantilever Code

There is some criteria the joists must meet according o the 2012 international residential building codes.

Maximum floor joist cantilever code.

Floor cantilevers supporting an exterior balcony are permitted to be constructed in accordance with table r502 3 3 2. The ontario building code cantilevered floor joists 9 23 9 9. 2 the cantilevered portions referred to in sentence 1 shall not. Floor cantilevers constructed in accordance with table r502 3 3 1 shall be permitted where supporting a light frame bearing wall and roof only.

Section r502 10 of the international residential code states that header joists can be the same size as the floor joists when the header joist span isn t greater than 4 feet but if the header joist span is more than 4 feet you ll need to double the header joist and ensure that it s capable of. The icc replaced the cantilever portion of the table in the 2018 irc with a maximum overhang length making the table similar to that in dca6. Maximum end notches for 2 x 8 2 x 10 and 2 x 12 respectively are 1 13 16 2 5 16 and 2 13 16. If the joists are lapped then they must be lapped at least 3.

Floor cantilever spans shall not exceed the nominal depth of the wood floor joist. A southern pine 2 2x12 beam can span 8 feet when supporting joists spanning a maximum of 14 feet and it can cantilever 2 feet beyond the posts on each side. For construction grade spruce one of the most common floor joist species a common building code is that floor joists that support dead roof loads and live floor loads cannot be extended beyond 16 inches for 2 x 8. Use either the 2018 irc deck joist span table or the joist span table in dca6 to size joists and cantilevers.

Additional support for the floor joists is achieved by nailing the ends of the joists into headers. 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. The joist must have a minimum of 1 1 2 riding on the wall or beam. 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.

A full depth rim joist shall be provided at the unsupported end of the cantilever joists. Building codes determine the maximum permissible cantilever span based on the size and species of lumber used for the floor joists. 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. You must use at least five framing nails to attach the rim joist to the ends of your joists.