My ceiling started to bubble and then crack in a spot. When I started to pop out those pieces to repair it, well I ended up with a good 12" by 12" area that came out. Under it was this cement like substance which I assume is plaster. Should I just skim coat over this with dry wall compound, sand and then paint? Or is there something else that needs to be done first.

I'm curious as to what made the ceiling fail in the first place.
Was it a poor repair that failed, water damage, etc.?
You could just skim the area and that should work, but you really need to find out what caused the failure.
If it was just a poor repair, then skim away.

No water damage that I can see. No staining under the paint or original skim coating that was there. I did notice that the original plaster had cracked slightly.

Is it in or near the bathroom?

I have seen them crack when there isn't an exhaust fan.

In the kitchen that has an exhaust hood about 5 feet away.

Do you have access to the back of the ceiling?

Look carefully if you can.

Repair methods depend on how large a gap you are trying to fill.

"good 12" by 12" area that came out. " sounds like drywall (or plaster) itslef.

What is behind the hole?  Air?  

I usually open anything more than 1 inch up to the nearest wood framing member on two sides.

Screw some sisters on the sides of the wood so you have 1.5 inch ledge to attach the new piece onto.

Install a piece of drywall or backer (plaster) screwed into the new wood strips.

For drywall close seams with setting compound (EasySand 90 if you are not experienced) and fiberglass mesh tape.

If you mix the setting compound with just enough water to make it combine (about as thick as smooth peanut butter) it will barely shrink when it sets.

It will take you at least two coats and possibly more depending on skill.


For plaster it just takes more filling.

Some Elmer's white glue cut 50% with water should be painted on old plaster edges.

Putting some on the face of the backer is OK also.

Wait till it is tacky but not dry and hard then fill the joint and cover the backer.  Old plaster will suck the moisture out of any repair material that touches it and make a weak spot.

Finish as well as you want.


I can make any kind of repair invisible.  

I have also been patching plaster (even 3-coat on wood) and drywall for 45 years though.

And I never sand anything.