Framing Cantilevered Floors

Closing in cantilevered joist spaces with solid blocking or panels above the supporting walls creates a cold cantilevered floor space.

Framing cantilevered floors. Figure 1 cantilever balcony although a cantilever should be calculated mathematically we need not go to the trouble if the length the distance out from the support is short. Floor cantilevers supporting an exterior balcony are permitted to be constructed in accordance with table r502 3 3 2. Floor cantilevers supporting an exterior balcony are permitted to be constructed in accordance with table r502 3 3 2. Floor cantilever spans shall not exceed the nominal depth of the wood floor joist.

Insulating the cantilever is not enough to ensure a comfortable floor air needs to move freely between the non cantilevered joist spaces and the cantilevered joist spaces in order to maintain a comfortable floor above the cantilever. Many building departments limit joist cantilevers to 24 maximum. Ensuring success air sealing of cantilever floor joist bays should be inspected by the site supervisor before the insulation and covering are installed. 69 chapter 4 floor construction woodframe floor systems and concrete slab on grade floors are discussed in this chapter.

You must use at least five framing nails to attach the rim joist to the ends of your joists. Rather the reader is referred to the aisi standard for cold formed steel framing prescriptive method for one and two family dwellings aisi 2001 for guidance. Floor cantilever spans shall not exceed the nominal depth of the wood floor joist. A cantilevered overhung floor area as shown in figure 1 such as a balcony presents a special problem that is easily solvable in residential construction.

Framing for floor openings a staircase is essential for commuting between floors but it creates an opening in the second floor so you can t run the joists from one side of the house to the other without interruption. 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. Floor cantilevers constructed in accordance with table r502 3 3 1 shall be permitted where supporting a light frame bearing wall and roof only. Cantilever floor construction detail showing where caulk should be installed in connection with framing and rigid air barriers to provide continuous air blocking.