Cutting Holes In Floor Joists For Plumbing

From the top and the bottom if it s a dimensional lumber joist.

Cutting holes in floor joists for plumbing.

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. 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. You also have to leave at least 2 in. Holes should have a diameter of no greater than 0 25 times the depth of the joist.

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. Drill holes with a diameter of no more than one third the depth of the joist staying 2 in. 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. Scan horizontally until you intersect the cor rect hole size column.

Area in the middle of the 2 10 joist where the hole can go. Holes should only be drilled on the centre line of the joist. Keep the hole at least 2 in. Area provided there are no other holes in the joist or notches along its top or bottom.

Permitted if the group perimeter meets requirements for round or square holes. Never drill top to bottom through a joist. Of solid wood between the top and bottom edges of the joist and the edges of any hole. They are located 3 away horizontally edge to edge from a larger hole.

Sometimes joists are notched at the end where they bear on a wall or sill. Rules for holes in joists. Tradespeople often need to cut notches or holes in floor and ceiling joists to run pipes ductwork or wires. Minimum distance from table b 1 round holes may be cut anywhere in web outside of hatched zone if.

Minimum applies to all holes except knockouts closely grouped round holes are. Away from the top and bottom. Check with the manufacturer as to the size of hole for the depth of joist rectangular holes are generally not permitted. This is where the compressive and tensile load distribution is neutralised.

Where and how to drill joists for electrical cables or plumbing runs depends on what type of floor framing you have. Measurement shown is minimum distance from edge of hole to support. 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. These joists may need reinforcin g to reduce bounciness sagging or excessive deflection in the floor or ceiling.

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. That gives you a 5 1 4 in.