Notches in the middle third of a floor joist are not permitted. Holes are not permitted to be located within 2 inches of the top or bottom edge of a floor joist. The maximum depth of a notch in a floor joist (that is not in the middle third of the joist) is the actual depth of the joist divided by 6. The maximum diameter of a bored hole through a floor joist (that is not in the middle third of the joist) is the actual depth of the joist divided by 3.