Cutting Holes In Floor Joists For Plumbing

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

Cutting holes in floor joists for plumbing.

Sometimes joists are notched at the end where they bear on a wall or sill. Holes should only be drilled on the centre line of the joist. Holes should be no closer together than 3 times the. For a 2 10 where actual depth is 9 25 inches the maximum allowable hole diameter would be just over three inches.

Scan horizontally until you intersect the cor rect hole size column. Using table a table b or both if required determine the hole shape size and select the tji joist and depth. Drill holes with a diameter of no more than one third the depth of the joist staying 2 in. Running wires or water supply lines through floor joists is a bit tricky but there is a way to cut the necessary openings through the joists safely.

Area in the middle of the 2 10 joist where the hole can go. Area provided there are no other holes in the joist or notches along its top or bottom. Of solid wood between the top and bottom edges of the joist and the edges of any hole. Away from the top and bottom.

Holes cannot be closer than 2 to the bottom or top of a joist or to another hole or notch in the joist drilling floor joists. Never drill top to bottom through a joist. You also have to leave at least 2 in. Although notches aren t allowed in the center third of a joist s length you can drill holes anywhere along the length of the floor joist in that 5 1 4 in.

The diameter of holes shall not be greater than 1 3 the depth of the floor joists. Where and how to drill joists for electrical cables or plumbing runs depends on what type of floor framing you have. Minimum applies to all holes except knockouts closely grouped round holes are. From the top and the bottom if it s a dimensional lumber joist.

Check with the manufacturer as to the size of hole for the depth of joist rectangular holes are generally not permitted. They are located 3 away horizontally edge to edge from a larger hole. These types of joists are engineered and their structural performance relies upon their integrity not being compromised. 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.

Where the property contains metal web joists as shown in fig 2 no notching drilling or cutting in either the timber flanges or the steel webs is permitted. These joists may need reinforcin g to reduce bounciness sagging or excessive deflection in the floor or ceiling. Rules for holes in joists. Permitted if the group perimeter meets requirements for round or square holes.

Minimum distance from table b 1 round holes may be cut anywhere in web outside of hatched zone if. Keep the hole at least 2 in. Holes should have a diameter of no greater than 0 25 times the depth of the joist.