Drilled hole in Load Bearing Ceiling Joist

21 Sep 2016
Reaction score
United States
Hi everyone! I'm new here and a new homeowner.

I was recently in the attic trying to drop an electrical wire to add a new light switch. In a rush and not thinking, I started drilling a hole in the exterior-facing ceiling joist with a 7/8" spade bit. After drilling ~2" deep, I stopped and panicked. I didn't drill through it, and I'm unsure how thick the joist is.

Btw, the hole is close to center of the length of the joist.

Did I make a major mistake? What can I do to repair it? Can I use some steel bracing?




Thank you for your responses!
Sponsored Links
It's not an approved place to drill, although people have got away with worse. If you're really worried go another way or get a structural engineer to do the calculations.
At the middle bending force is greatest whereas at the ends shear is greater.
If you're drilling for t&e then use a smaller bit anyway!
what's the depth of the joist, in reality you probably wont have done any harm particularly of its just the one hole finish it off and put your cable through
Not a good idea, but I doubt that half done hole will cause anything to collapse.
Look on here and see some of the enormous chunks people find plumbers and sparks have chopped out of joists, way more than the recommended amount but they get away with it without a disaster.(y)
Sponsored Links
Thanks all for your replies! It eases my mind a bit :)

Yeah should have used a smaller bit ... And not drilled the joist in the first place!! Not sure of the joist's depth.
you could plate the hole either with metal or ply. just for peace of mind

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local