You can drill the holes anywhere along the length of the joist (first photo). If you have manufactured I-joists, you can drill holes up to 1-1/2 in. diameter almost anywhere in the web area (the area between the flanges). Just stay 6 in.Jun 30, 2017

Can you drill holes in joists for electrical?

For the engineered I-Joists shown in Fig 1 some of the limitations are: Do not notch or drill holes through the top or bottom flange. It is generally permissible to drill up to 38mm holes anywhere in the web.

How close to the end of a joist Can I drill a hole?





Don’t make any holes with a diameter greater than 1/3 the depth of a joist. ‘ No holes closer than 2 inches to the top or bottom edge. No holes closer than 2 inches to any other hole or notch.

Can you run wire through floor joist?

To run cable through a floor that contains a cross joist, cut a hole in the cross joist in the cavity closest to the cable`s entry point. Then, run the cable through the hole in the cross joist and through 1/2-inch holes in each joist between the entry point and the communications outlet.

How big of a hole can you drill in a floor joist?

Rules for boring/drilling holes



You can put holes in floor joists anywhere along the length of the joist, but you can’t put them any closer than 2″ from the top or bottom edge of a joist. The maximum size of a hole is 1/3 the depth of the floor joist.

How big of a hole can you drill in a 2×10 floor joist?

The maximum allowable diameter of a hole in any solid-lumber joist is one-third of the joist’s depth. Notches can’t be deeper than one-sixth of the joist depth. In the case of your 2×10 joists, the maximum diameter is 35⁄64 in.

Does screwing into a joist weaken it?





When weight is applied to a joist, the top edge goes into compression while the bottom edge goes into tension. Improperly sized or placed holes and notches weaken the joist, make it bouncy and saggy, and provide an easy place for it to crack and fail.

Can I drill a 3 hole in a 2×10 floor joist?

Simply following building code, you’ll only be allowed to bore a 3-5/64″ hole through a 2×10 joist. A 2×10 is actually only 9-1/4″ deep, and building codes set the maximum hole size to 1/3 the depth of the member (9-1/4″ / 3 = 3.08333″).

Can plumbing go through floor joists?

Running drainpipe through joists calls for meticulous work. The holes must follow a straight line across the floor and must ascend or descend so the pipe will be sloped 1/4 inch per foot. (If joists are 16 inches on center and pipes run across them at a right angle, holes should differ in height by about 3/8 inch.)

How much can a floor joist be notched?

Notches on the ends of joists shall not exceed one-fourth the joist depth. Holes bored in joists shall not be within 2 inches (51 mm) of the top or bottom of the joist, and the diameter of any such hole shall not exceed one-third the depth of the joist.

Where do you notch a floor joist?



Rules for Notches in Joists

  • Notches should only be made in the top edge of the joist.
  • Notches should be no deeper than 0.125 times the depth of the joist.
  • Notches should be no closer to the structure supporting them than 0.07 times the span of the joist.
  • The notches should be no further away than 0.25 (¼) times the span.


How big of a hole can you drill in a 2×8?

2 3⁄8 inches



In a 2×8, for example, the maximum hole diameter is 2 3⁄8 inches (actual rather than nominal dimensions should be used to make these calculations).

What are the codes for drilling or notching joists?

Holes bored in joists shall not be within 2 inches (51 mm) of the top or bottom of the joist, and the diameter of any such hole shall not exceed one-third the depth of the joist. Notches in the top or bottom of joists shall not exceed one-sixth the depth and shall not be located in the middle third of the span. R502.

Can I drill holes in my floor joists?

You can drill the holes anywhere along the length of the joist (first photo). If you have manufactured I-joists, you can drill holes up to 1-1/2 in. diameter almost anywhere in the web area (the area between the flanges).

Can a floor joist be notched?

You can cut a notch at the end of the joist to 1/4 of the joist’s depth (maximum). Along the outer third of a joist, you can cut a notch a maximum of 1/6 the joist depth and 1/3 the joist length without compromising its strength.

Where do you notch a beam?




Quote from Youtube video: But with a notch you can go into the edge as long as the notch is not bigger than one-sixth. The height of that joist.