When it comes to unsightly crevices and holes on a plaster ceiling, a significant number of people actually consider having it fixed by a professional. If there are a lot of cracks, then that option is definitely one to take; however, if all we’re talking about is less than a dozen of them, you can actually do the fix yourself.
Plaster is a material which can be relatively easy to work with even if it is already set. In other words, you shouldn’t be intimidated by it when you try to make some repairs on it. All you will need is a little amount of time, in addition to some common tools and materials.
Regardless of how bad the crack is, there are two phases to take when making a repair: Filling the gap, and retouching. This is usually easier than it sounds, especially in the case of small and minor cracks or holes. All you would have to do is to patch them up with a substantial amount of quick drying compound. You can easily apply this material with a taping knife. After filling up the gap, don’t forget to smooth it over. You would have to wait for a good amount of time after that to let the material dry.
Once that is dry, you will need to sand the area with a sanding block. Or, if you have an orbital sander that would definitely work fast and well too. Just make sure you use sandpaper which is between 80-100 grit. After sanding, dust off the area, and coat it with some drywall compound.
Fixing bigger gaps follows the same concept, but it just takes a little more time. Take an edged tool and undercut the insides of the crack. This will ensure that the drying compound that you will be applying would bond better with the plaster. Speaking of drying compound, do not fill the gap. Using the proper tool, take some of the compound and spread it on the insides of the crack, making a thin layer. Take a portion of fiberglass tape and embed it in the compound, thus filling the crack and preventing it from getting worse.
Cover the whole area with another coat of the drying compound, and make sure to feather it so it is as even as it could be with the ceiling’s surface. Leave the whole area to dry when this is all accomplished. It shouldn’t take more than a day, but it depends on the size of the crack you are fixing up. Nevertheless, once the area dries up, you can use a sanding block, or an orbital sander to smooth it. Wipe the area of dust, and apply another thin layer of more drying compound.
After performing these steps and ensuring everything is dry, sand the whole area just one more time to make sure the area is smooth and even with the ceiling’s surface. Don’t forget to apply some varnish or an initial coat of paint over the area. This would prepare it for further painting or sizing (in the case of wallpapering). The area should look like it never had a crack in the first place.