Cutting Floor Joists

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.

Cutting floor joists.

Notches will compromise the strength of the new joists but some notches are acceptable depending on their location. Sometimes joists are notched at the end where they bear on a wall or sill. As a remodeling contractor and carpenter one common structural framing issue i see alot of in bathroom remodeling jobs are floor joists that were cut drilled notched or need to be cut out to accommodate plumbing pipes and drains. Make sure not to install joists so they run parallel to and directly under walls where you intend to install ductwork.

Nailing two 2x4s together will work to span about three joists unless the sag is under a weight bearing wall. Framer jim anderson demonstrates solid techniques for cutting floor joists to length quickly and accurately. Tack a beam under the sagging joists. In order to maintain the support integrity of the ceiling or floor joist or rafter system it is important that if joists are cut that the load that was bearing on those joists be transferred to a modified support system.

These joists may need reinforcin g to reduce bounciness sagging or excessive deflection in the floor or ceiling. Cutting and or removing joists to provide an entry or access can be the most difficult part of the overall project. In situations when sistering damaged floor joists with lumber of similar dimensions it can be easy to notch and slide the sister board into place. This will create a weak spot.

Apa performance rated i joists pris are manufactured in accordance with pri 400 performance standard for apa ews i joists form x720 this performance standard provides an easy to use table of allowable spans for applications in residential floor construction allowing designers and builders to select and use i joists from various member manufacturers using just one set of span. Structural floor joist repairs. Pry the floor joist from the subfloor with the back of your hammer. Then use pry bars and your reciprocating saw to pry and cut the floor joist away from the subfloor.

If you need to cut through a joist firm up the floor as shown in fig. Start by cutting out a small 1 2 in 2 5 5 1 cm section of the floor joist with a reciprocating saw. Then set new joists same height as existing ones alongside the old. To minimize problems with ductwork.

If the cut outs are too large or in the wrong location the joist can be weakened and unable to support the load it was designed for. Position bathroom vent fans so the ducts can run parallel to the joists right up to where they exit the house.