Can I Notch A Floor Joist

You can notch and bore joists without sacrificing critical strength but you must follow the rules.

Can i notch a floor joist.

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. Floor joists constructed from large dimension lumber bear the weight of the structure above so notching them isn t recommended. However doing this does not fix the slant that the floor has taken since the old joists got damaged.

Holes bored in the joists or rafters shall not be within 2 inches of the. From the side they look like a steel i beam. No notches deeper than 1 6 the joist depth. But there are strict guidelines for notching or cutting holes in engineered floor joists.

They utilize a lot of glue which is why the fire department does not like them if they get too hot. Some things to consider are the length and depth of the notch you plan to remove the condition of the existing joists an examination to determine whether they are underspanned to begin with and the possibility of sistering full width and full length members to the trimmed joists. 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.

No notches in the middle 1 3 of the joist but holes are permitted here. No holes closer than 2 inches to any other hole or notch. If your home is more than 20 years old your floor joists are most likely solid wood 2x8s 2x10s or 2x12s. No end notches where the joist is supported greater than 1 4 the joist depth.

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. 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.