Drywall seams can crack and separate for many different reasons. A cracked foundation will cause this, as will improper drywall finishing in the first place. It might even be that the hanger did not use enough nails or screws. If your problem is with your foundation it makes sense to fix that before worrying about your drywall seams. A foundation problem is serious and will cause doors and windows to not open and even roof problems.
When drywall is nailed or screwed to the studs in your home, there will be a seam every four feet in one direction and every eight to twelve feet in the other direction and on all inside corners. It adds up to a lot of seams and a potential for a lot of cracking. Don’t worry though, patching things up is easy (and for some of us, fun).
What You will Need
To complete this project you will need a variety of items but nothing too costly. At the minimum, for tools you will need a taping knife (six inches is a good choice), a utility knife, any kind of scraper, a mud pan, and perhaps a ladder depending on where your seam problem is. You will also need to sand. Preferably you should use a sanding pole and sanding screens, but for repairs like these you can get away with regular sandpaper.
You will need mud or drywall compound. This comes in powder form in a bag or premixed in plastic buckets. I recommend the premixed. Drywall tape finishes off your list. There are two types: paper or mesh with adhesive backing. I recommend the mesh; it’s easier to work with because of the adhesive and I just feel that it works better. Paper is no good for a beginner.
Using your scraper, remove any texture from the seam four inches from the center of the seam in both directions and for the length of the crack plus a couple of inches in either direction. You can tell how wide the tape is from looking at the tape you bought for the repair.
That is just about the width you will need to cut out from the seam. What you are doing is making a depression in the wall for the repair tape to fit into so that you won’t end up with a bulge but a flat, level surface. So, using your utility knife, cut out the old tape where the seam is split.
Go ahead and put some mud in your pan from the bucket. I find the mud easier to work with if I thin it out just a tiny bit. Put just a tiny splash of tap water in with the mud and mix it in using your taping knife.
Time for the Repair
Cut a piece of tape from your roll to fit the area you prepped (spanning the seam). Apply it using the adhesive to hold it in place. Now scoop a small bit of mud onto your knife and paste it onto the tape. Continue until it is worked into the whole piece of tape. You are not filling the void at this point. This is the “taping” phase of the “taping and floating” process. All you are doing is integrating the tape with the joint.
Now you can clean your taping knife and pan with water while the mud dries. Hint: after cleaning and wiping down your knife, give it a little spray of WD-40 and wipe with a paper towel. If your blade gets even a speck of rust on the edge, it will be useless for finish work.
When the mud is dry, sand off any dried mud ridges you may have left and float the joint. What you are doing here is layering on enough mud to cover the taped area and have the repaired section of wall flush and even with the rest of the wall. Let it dry and check it out. If it is not satisfactory, repeat. Finishing is something of an art.
Wrapping It Up
Once you’ve got it looking sleek, match the texture using the mud. This is also an art form but try different things until you are happy. One trick is to dab the wall with a paint brush, let it dry, and then lightly sand. Experiment. Finish off by painting and then admiring your work!