Notch A Floor Joist

Corbeling is an old school overlapping arrangement of bricks with each course extending farther out from the vertical of the wall than the course below.

Notch a floor joist. Floor joists constructed from large dimension lumber bear the weight of the structure above so notching them isn t recommended. In fact most have little perforated knockout holes that can be punched out with the swing of a hammer. You can never ever ever notch or bore through the top or bottom flange or chord. 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.

Improper notching can weaken a floor joist. Holes anywhere in the web. Sometimes joists are notched at the end where they bear on a wall or sill. Rules for notching joists the joist notch and hole calculator.

These joists may need reinforcin g to reduce bounciness sagging or excessive deflection in the floor or ceiling. In some cases a plumber or another mechanical contractor might. You can drill 1 1 2 in. Notching wood and boring rules engineered i beam rules.