Cutting Holes In Floor Joists

Tradespeople often need to cut notches or holes in floor and ceiling joists to run pipes ductwork or wires.

Cutting holes in floor joists. Cutting notches and drilling holes in joists. Minimum applies to all holes except knockouts closely grouped round holes are. 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. Permitted if the group perimeter meets.

Of walls and rim joists. The diameter of holes shall not be greater than 1 3 the depth of the floor joists. Trus joist tji joists. For a 2 10 where actual depth is 9 25 inches the maximum allowable hole diameter would be just over three inches.

They are located 3 away horizontally edge to edge from a larger hole. Often hole size can be increased and holes can be placed closer to bearing than shown on the chart based on actual design spans and loads. Cutting and or removing joists to provide an entry or access can be the most difficult part of the overall project. A hole saw is a short tube shaped cutting tool with drill bit through the center of the cylinder and a.

Rules for holes in joists. If you have manufactured floor joists you will want to consult the particular manufacturer s literature. Where and how to drill joists for electrical cables or. 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.

Minimum distance from table b 1 round holes may be cut anywhere in web outside of hatched zone if. Away from the top and bottom. Holes cannot be closer than 2 to. As part of any new installation work or a re wire a cable trunking or cable tray sometimes has to pass through an element of building construction such as a floor wall or beam necessitating the formation of a notch or opening in the element.

Refer to the hole chart on page 9 of the tji specifiers guide for uniformly loaded joists. Drill holes with a diameter of no more than one third the depth of the joist staying 2 in. Please follow these rules for making holes in joists. If the joist is 12 inches deep you need a hole saw that is 4 inches in diameter or smaller.