There are just some projects you put off. You tell yourself it would be the perfect project for a rainy day. A decade later there have been plenty of rainy days, but the project still isn’t started. Then a loved one points out the unfinished project, and you honestly can’t remember that it ever needed to be done. Out of sight often leads to out of mind. This is all hypothetical, of course. But let’s say that this project involves repairing a hole in drywall, and you’re not sure how to repair it. So for all the “hypothetical” drywall holes to be fixed, here’s a Pro tip on how to patch a large hole in drywall.
In this example, the removal of a vent for an old air conditioning system left a large hole. The same repair principles apply to damage caused by a doorknob, water leak, or random fit of rage.
How to Patch a Large Hole in Drywall Step by Step
With our example, the cutout had the added bonus of having an electrical wire running behind it. It won’t really be in the way of the work, but we still need to be careful not to damage it.
Step 1. Square Up Your Drywall Hole
With a doorknob repair, you’d want to make the hole square using a keyhole saw or your favorite multi-tool. Larger holes work the same way. You need a clean rectangle or square in order to cut a replacement piece that fits easily into the space. For these, we reach for our go-to utility knife and clean up the edges as needed.
Be sure to also check out our article 6 methods for cutting drywall.
Step 2. Add a Backing Board…or Two
Before you even think of adding any new drywall, you need to consider fastening a piece of wood behind the drywall. Depending on the size of the hole, you want to ensure you have enough places in which to fasten the patch and ensure the drywall doesn’t crack later. For large drywall repairs, we recommend widening the hole to the center of your studs. This makes it much easier to secure the new piece when you’re ready. When that’s not possible, adding a board to one of the sides and/or center can help.
Adding wood in the form of a wide furring strip gives you a nice fastening point to hold the patched piece of drywall. We added one in the center and also off to the right side. The left side already had an exposed stud.
Simply hold the boards in place, and then screw through the drywall to secure them tightly to the inside of your drywall.
3. Dry Fit the Drywall Patch
We really like to make sure the patch fits before proceeding. You will find it much easier to cut the drywall when it’s away from the wall. If you have to bang it into place, you’re likely to crush or dent the corners—making it harder to finish.
4. Fasten Your Large Drywall Patch to the Wood
Once you know you have the patch cut to the right size, place it into the hole. Fasten your large drywall patch to the wood and/or studs using coarse thread drywall screws. It should be a snug fit, and you want to make sure you have stability around the perimeter of the patch. This keeps it from moving and cracking later.
5. Use Tape or Screen Material to Cover the Patch
You want to reinforce any drywall seams for stability. We recommend using screen material or simply drywall tape. This prevents the joint compound from cracking as it dries. It’s also important to apply the compound in thin layers. You can use a full screen for a small patch, or use mesh tape to cover the perimeter of a large patch.
6. Apply Joint Compound Using a Drywall Knife
Apply the first coat of joint compound in a thin layer using a wide putty or drywall knife. We recommend 10-inches unless the patch size is small. Make it as smooth as possible. After it dries, it’s likely you’ll still need to sand rough spots and apply another thin coat. Repeat this until it blends with the wall. Avoid trying to do this all in one pass unless you really know what you’re doing—in which case, you should be adding your wisdom below after reading this!
Wrap It Up
We hope you can start on those hypothetical projects that you’ve been putting off. If knowing how to patch a large hole in drywall helps, then we’ll consider this a “win”. Also, if you’re a Pro reading this and you have any drywalling tips, please add them in the comments below.
