Can I Notch A Floor Joist

No notches in the middle 1 3 of the joist but holes are permitted here.

Can i notch a floor joist. They utilize a lot of glue which is why the fire department does not like them if they get too hot. If your home is more than 20 years old your floor joists are most likely solid wood 2x8s 2x10s or 2x12s. Notches should be no closer to the structure supporting them than 0 07 times the span of the joist the notches should be no further away than 0 25 times the span. No end notches where the joist is supported greater than 1 4 the joist depth.

But there are strict guidelines for notching or cutting holes in engineered floor joists. However doing this does not fix the slant that the floor has taken since the old joists got damaged. In some cases a plumber or another mechanical contractor might. No notches deeper than 1 6 the joist depth.

You can notch and bore joists without sacrificing critical strength but you must follow the rules. This is to avoid the area of maximum shear force and the area of maximum bending in the joist the rules for positioning notches in floor joists image courtesy of niceic. The length of a notch should not exceed 1 3 the joist depth. When piping or ductwork is placed in or partly in an exterior wall or interior load bearing wall necessitating cutting drilling or notching of the top plate by more than 50 percent of its width a galvanized metal tie not less than 0 054 inch thick 1 37 mm 16 ga and 1 1 2 inches 38 mm wide shall be fastened across and to the plate at each side of the opening with not less than eight.

Notching and boring of joists and rafters section 91 2308 8 2 joists 91 2308 10 4 2 rafters b notches at the ends of joists or rafters shall not exceed one fourth the depth. No holes closer than 2 inches to any other hole or notch. 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. Floor joists constructed from large dimension lumber bear the weight of the structure above so notching them isn t recommended.

The notching and boring rules of thumb for solid lumber are shown in fig. There is a top and bottom section with a vertical member in between.