How to Cut Holes in Drywall for Electrical Boxes

November 16, 2015

 

A couple of tools and some techniques on cutting clean electrical work boxes every time

Hanging drywall is something that every remodeler does more often than they want to. Full sheets are fine, but switch boxes and outlets complicate the process. Myron Ferguson, maybe the most enthusiastic drywall guy ever, shows us how to locate and cleanly cut the boxes.

Because if you don't cut them clean, you're coming back to clean up your mess. This takes time and makes you look like a rookie. #NotGood.

 

OFFICIAL HIGHLIGHTS:

The number one thing to be careful of, whether cutting boxes with a saw, knife, or drywall router is to not cut the wires. Make sure that they are tucked into the box, if the electrician did not do so already.

The switch plates and outlet covers will not cover much more than a 3/16 in. gap around the box, so if the cut is sloppy, you will have to come back to patch it. 

 
Don't precut holes in the drywall

The best way to accurately cut the hole for an electrical box is to cut it after the drywall is tacked into place.

It seems simple to take measurements and transfer them to the drywall, but drywall has a way of not following the plan, so you end up with gaps and call backs.

Keep fasteners away from the box to reduce the amount of pressure against the drywall. If the sheet is too tight against the box, it can break while you are cutting.

Instead, mark box locations on the floor before hanging the drywall. Mark the center of the box and then add numbers to indicate the height of the center of the box.

For switches that are close to the edge of a panel, you can just peek behind the drywall to see where the box is, but the markings on the floor are a good double-check to make sure you don't miss (bury) any boxes. 

 
How to use a drywall router to cut out the box:
  1. Insert the bit at the center mark of the box.
  2. Slowly rout over to the edge of the box.
  3. Jump over the edge of the box and rout counter-clockwise following the outside of the box.

 

A couple of tools to find boxes
  • Blind Mark Drywall Electrical Box Locating Tool Kit is a megnet-based kit that allows you to trasce the outside of the box.
  • Mark-N-Guard protects the wires and pokes a hole through the drywall in the center.

 

It is important to get it right the first time because each repair can take ten minutes of your time. If you have 200 boxes in a house (probably a low number) and you need to make repairs on 10% of them. that is (20 repairs) x (10 minutes) = 200 minutes, or about a half day.

 

—Myron Ferguson, aka That Drywall Guy, points out on his website that over 80% of the visible interior of a home is covered with drywall, and  "The bitterness of poor quality remains long after the sweetness of low price is forgotten."
Amen, brother.

 


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