Cutting Holes In Floor Joists

In order to maintain the support integrity of the ceiling or floor joist or rafter system it is important that if joists are cut that the load that was bearing on those joists be transferred to a modified support system.

Cutting holes in floor joists. The diameter of holes shall not be greater than 1 3 the depth of the floor joists. Of walls and rim joists. Minimum applies to all holes except knockouts closely grouped round holes are. 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.

They are located 3 away horizontally edge to edge from a larger hole. 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. A hole saw is a short tube shaped cutting tool with drill bit through the center of the cylinder and a. If the joist is 12 inches deep you need a hole saw that is 4 inches in diameter or smaller.

Where and how to drill joists for electrical cables or. For a 2 10 where actual depth is 9 25 inches the maximum allowable hole diameter would be just over three inches. Rules for holes in joists. 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.

Permitted if the group perimeter meets. Cutting notches and drilling holes in joists. Holes cannot be closer than 2 to. Sometimes joists are notched at the end where they bear on a wall or sill.

Holes anywhere in the web area of engineered i joists except within 6 in. Refer to the hole chart on page 9 of the tji specifiers guide for uniformly loaded joists. Cutting and or removing joists to provide an entry or access can be the most difficult part of the overall project. Minimum distance from table b 1 round holes may be cut anywhere in web outside of hatched zone if.

Drill holes with a diameter of no more than one third the depth of the joist staying 2 in. Away from the top and bottom. Trus joist tji joists. Tradespeople often need to cut notches or holes in floor and ceiling joists to run pipes ductwork or wires.