- Q.What’s the largest
hole I can drill in a 2x8 joist? What about notching?
Also, how close to a bearing point can I drill a
Paul Fisette responds: The rule that most
codes use is that holes can’t be any
closer than 2 inches from the top or bottom of the
joist, and cannot be within 2 inches of any other
hole. If the joist is notched, you can’t
drill the hole within 2 inches of the notch. The
hole’s diameter can’t exceed
one-third of the joist depth. So in your case, the
largest hole would be 2 3/8 inches.
Notches in the top or bottom of a joist
can’t exceed one-sixth the depth of the
joist and can’t be longer than one-third
the joist depth. Notches must not be made in the
middle third of the span. If a notch is made at the
very end of the joist, it can’t exceed
one-quarter the joist depth.
As always, check your local code to make sure
it’s in keeping with the norm.