Drilling Holes In 2x10 Floor Joists

Drill a hole large enough and pull the cable through.

Drilling holes in 2x10 floor joists. The hole cannot be larger than one third the depth of the joist so the maximum hole size for a 2 12 joist actual size 1 1 2 x 11 1 4 in is 3 3 4 in. The rules for positioning notches in floor joists image courtesy of niceic to understand the forces at work in a joist particularly the tension and compression forces please see our project that explains how the forces that affect buildings work. The diameter of holes shall not be greater than 1 3 the depth of the floor joists. The hole must be 1 1 2 from the edge of the joist to prevent nails or drywall screws from penetrating the cable.

But modern living requires electrical wiring and plumbing. In a perfect world floor joists are left whole to provide the greatest support. Please follow these rules for making holes in joists. Floor ceiling rafters 7 8 1 3 8 1 13 16 2 5 16 2 13 16 depth of notches located between the ends middle 1 3 of the span 9 16 15 16 1 3 16 1 9 16 1 7 8 length of notches.

You can drill the holes anywhere along the length. 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. Sometimes joists are notched at the end where they bear on a wall or sill. Diameter plenty big enough for running cable.

For a 2 10 where actual depth is 9 25 inches the maximum allowable hole diameter would be just over three inches. In floor joistsand table 1. Notches should be no deeper than 1 6 the depth of the joist. From the top and the bottom if it s a dimensional lumber joist.

1 you are not allowed to drill in the middle third of the span at all. Tradespeople often need to cut notches or holes in floor and ceiling joists to run pipes ductwork or wires. Maximum sizes for cuts in floor joists holes do not bore holes closer than 2 from joist edges nor make them larger than 1 3 the depth of the joist. Notches do not make notches in the middle third of the span where the bending forces are greatest.

The holes can not be larger in diameter than 1 3 the actual depth of the joist. For a 2x10 that would mean a hole no larger than 3 5 32 diameter. How to drill a hole through the side of a floor joist. Holes cannot be closer than 2 to.

Keep the hole at least 2 in. Bored holes for floor joist ceiling joist rafters 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12 depth of end notches.