Cutting A Floor Joist Out Of The Floor Above

Finish cutting out the square by cutting parallel to the joists inside.

Cutting a floor joist out of the floor above.

If your home is more than 20 years old your floor joists are most likely solid wood 2x8s 2x10s or 2x12s. Cut into floor along the lines between the joists but several inches inside your marks for the centerlines of the joists. The space between the beam and the floor boards above was 7 inches so i decided to use regular framing lumber and rip a 1 2 inch off the width of a 2 8 framing member. Such is the case with this house after a small electrical fire.

A nominal 2 8 board measures 1 1 2 by 7 1 2 inches cutting the new joist. I was careful not to cut too deep where i suspected the floor joists were and came back and finished cutting over the top of them with the reciprocating saw laid down as much as possible. Each type of floor joist offers its own unique benefits and drawbacks which is why those working in carpentry all tend to have their own favorite floor joist option though they are still required to be well versed in each type of floor framing. But sometimes you have to cut out an old floor joist and put in a new one.

Codes don t directly address how many holes and notches you can cut in a joist. The three main types of floor joists used in home construction are solid lumber i joists and open web floor trusses. The notching and boring rules of thumb for solid lumber are shown in fig. The only problem was the subfloor was nailed to the floor joist with some very large nails and they did not come out very easily.

The fire burned through a section of one of the floor joists and the homeowners wanted to replace it without tearing up the finished wood floor and subfloor above.