Should You Drill Floor Joists

For this discussion we will focus on the traditional dimensional floor joists.

Should you drill floor joists.

This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction. No greater diameter than 0 25 times the depth of. As part of any new installation work or a re wire a cable trunking or cable tray sometimes has to pass through an element of building construction such as a floor wall or beam necessitating the formation of a notch or opening in the element. Cutting notches and drilling holes in joists.

How to position holes correctly so they don t weaken the joist. If you have manufactured floor joists. Measure up 2 inches from the bottom edge of the joist and mark it again. You can t notch or drill them anywhere.

If you re remodeling or building with i joists your lumber supplier can provide you with a set of hole drilling standards to follow. For those working with the less common open web or floor truss joists fig. Rules for holes in joists. Mark the joist at that spot with a pencil.

Guide to making safe cuts holes and notches in floor joists and ceiling joists. You can safely drill joists for electrical and plumbing runs without weakening the joists if you follow the rules. How to drill through floor joists. The guidelines for these are shown in fig.

Measure down 2 inches from the top edge of the joist. Irc r502 8 and irc r802 7. B the guidelines are simple.