Let’s face it. Plaster sucks. Some people may think horsehair plaster is sacrosanct, and all the fervent restoration folks will want to kill me for saying it. But I just don’t like the stuff. It’s really dusty and flaky, and a pain in the butt to fix. Originally made of lime, horse hair, and gypsum, it was used extensively throughout our house. Drywall and joint compound is much easier to work with. And much easier to sand, since they make “easy sand” versions of joint compound.

Our bedroom ceiling had a fairly large crack in the ceiling. After finishing 2 bathrooms, and fixing other walls around the house, I was getting pretty good and confident about my abilities to “skim coat.” The real professionals usually apply 3 coats of compound when drywalling or plastering. I’m kind of lazy and I did not mind sanding. After all, everyone will need to sand at some point.

Anyway, back to the ceiling. The first thing is to secure the ceiling. The plaster is cracked for a reason. Some of the “keys” to the plaster were probably broken and the ceiling had some movement to it when pressed. To secure the plaster to the laths, I used plaster washers or ceiling washers. They’re basically thin, oversized washers with many small holes in them (to let the plaster or compound seep through them). Screw the washers into the laths, if you miss a lath, no worries. Just pull it back out and try a different location.

plaster washers in ceiling

I put in about a dozen or more the washers on both sides of the crack. The ceiling should not give when pushed. Then I cleaned out the crack, getting any loose plaster or dust out. I even made the crack larger in some spots. This will get filled eventually. It’s also a good idea to put in mesh tape along the crack (I forgot but it seems fine without). Next use joint compound and cover it up. I used an easy sand 90 minute cure joint compound (I’d probably recommend the 45 minute one). When applying, be generous with the compound, especially if you only want to use 2 coats and not 3 coats. Then skim it over with the widest putty knife you got. I had a 10″ one, but a 14″ or 16″ is even better. Don’t worry about small ridges or some air pockets with the first pass. Feather out the sides.

joint compound over crack

The area should span at least a foot past the crack in both directions (so at least 2 feet total) to make the final product blend in. The first pass looks rough, but I don’t mind. After a few hours (up to a day or more - depending on the compound used), it should be dry and ready for sanding. Sand all the rough edges smooth and sand the outer areas of the compound to make it feather seamlessly into the rest of the ceiling (the feathering is the most important part). Then apply another layer of compound, filling any holes and patching things up. When that’s dry, just sand it again. Run your hand over the area to make sure there are no big bumps, protrusions, or holes. If you’re not satisfied yet, by all means apply another coat and sand. You’re not going to have a perfectly flat ceiling, but as long as it’s feathered and sanded properly, no one will be able to tell.