2x8 Floor Joist Cantilever

With triforce it is possible to construct a cantilever perpendicular to the joists by using 2x joists inserted through the open webs of the joists.

2x8 floor joist cantilever.

But you ll notice when you look at the portion of the span table for joists with cantilevers that the joist span for decks with a cantilever is often less than the span for the same sized joist without cantilevers. Because existing floor joists ran parallel to the bump out it was possible to sister 2x8 douglas fir joists to the existing floor joists to create the cantilever. The outside cantilevered joists are doubled as is the rim joist. Cantilevered floor joists h1 2 treated l.

In this video i wil. Theoretically it could cantilever 40 x 10 4 feet beyond the supporting beam. Code says 2ft cantilever can be done with 2x8 joists. Any more and it may be bouncy.

Many building departments limit joist cantilevers to 24 maximum. Branz recommends that all cantilevered joists have continuous blocking. 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. If the cantilever is being extended from the trimmable i joist end of a triforce joist a 5 8 wood filler is required on the osb panel.

Using stiffer lumber types such as yellow pine douglas fir or hemlock would add stiffness. 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. An example of this would be a joist that spans 10 feet between supports. At the line of the cantilever support wall.

Yellow pine is widely available in treated lumber. Cantilevered joists in an enclosed space. I think 3 ft would be okay. Section r507 5 notes that deck joists can cantilever up to 1 4 of the joist span.

Thus a 10 4 14 foot joist would be possible. The back span of the sistered joists is in a two thirds ratio to the bump out or 7 ft. But if the joist is a 2x8 with an actual width of 7 25 inches then the cantilever would be limited to 4 x 7 25 29 inches. With the allowable cantilever of the joists this beam would support a deck 12 feet by 17 1 2 feet.