When we put in a fireplace on the first floor, the chimney extended up through a corner of our bedroom. We drywalled around it and wall papered it. Several years ago, we had to cut a hole in the drywall about 4" x 6" to fix a chimney problem. I'm getting ready to redecorate and am wondering if there is a way I can repair the hole in the drywall.

 

To make this repair you'll need a screwgun, or a drill with a #2 phillips screwdriver bit, one of those plastic mud pans, and I'd recommend a 6", 10", & 12" drywall knife. You'll need a piece of drywall large enough to patch the hole. It's crucial that you use the same thickness of drywall for the patch as what's already up. Walls are generally 1/2", ceilings generally use 5/8", you should measure the thickness of the sheet at the hole to determine what you will need.

You'll also need a few drywall screws, (I'd suggest 1-5/8" screws, commonly referred to as inch-fives), a small pail of drywall joint compound, I use paper drywall tape, but alot of diyers opt for the mesh tape, as it will stick directly to the seams w/o pre-mudding them, so that is what I'll describe here, and you'll need some length of board a little longer than the hole size, known as backing.

Put the board thru the hole, & run screws thru the existing wall into the board on both sides. I usually use 2 pieces of backing, one on each side of the repair. Now trim the patch so it fits the hole. Once you've got it trimmed to fit, attach it to the backing with screws. It's important that you set your screws so they just slightly dimple the face paper of the drywall, run them too deep & they'll thru everything, not deep enough & they'll protrude up thru & be exposed after mudding.

Once you've got the patch all screwed in, cut some pieces of the mesh tape to cover the seams of the repair. Now coat with mud, you'll need to use 2-3 coats to completely cover the patch.
With each coat use a larger knife to feather out the mud & blend it in. Between coats, let the mud dry & then just run a drywall knife over it to knock off high spots & possibly a LITTLE light sanding.

After the final coat, sand smooth, & then apply primer over the repair & paint.

 

You have explained this very well. By golly, I think I can do it! The drywall joint compound is what you're calling "mud", right?

 

Yeah, I use USG lite mud, you can also use the all-purpose, but you have to thin it more with water.

Any kind you use needs to be thinned with some water. For a small patch like this you could also opt for using a setting type compound. This comes in a bag, Easy-Sand 90, is what I'd recommend for a first timer. Thing is it drys very fast & sets, the 90 stands for the setting time, it also comes in 15min, 45 min, etc, but I'd stay with the 90.

It's a powder & you just need to mix small amount with just enough water to get it to like a thick batter consistency.

If you use the regular lite joint compound, you also should thin it just a bit with water, for your size of a patch get one of the small like 1 gal pails of the stuff from a home center or lumber yd. Dump it into a clean 5 gal bucket & add just like a cup of water, & mix to proper consistency again like a thick batter.

Regular joint compound will require several hours to dry completely, in a climate controlled room, you should be ok the next day to apply second coat, same for the third. If you have a lid for your mixing bucket, put it on it at night, next day a short remix & the same mud is ready to use for the next coat. If you don't have a lid, use a plastic bad & some tape to seal off the bucket & save the mud for reuse.

You can do this, have faith!

For mixing small batches like this I'd recommend getting a small mixing paddle which can be attached to your drill. Again can be picked up at home centers, hardware, lumber dealers.

 

After I reread the directions there is one thing I can't figure out. You put the backing board behind the old drywall and attach it with screws. Don't the screws show on the existing wall?

 

Yeah they will be a couple maybe 3" out from the existing hole in your wall and the visible screw heads get covered with mud during the process. Remeber to sink all screws just enough to dimple the face pape, but not break it.