I have a plaster & lath ceiling in a bedroom that is in need of repair - it's intact for the most part, but it's pretty unsightly. Since the entire ceiling is full of cracks, I'd rather simply cover it with a layer of 1/2" sheet rock.

Would the drywall be sufficient to clamp the sagging parts to the lath/studs, or should I use plaster washers and then attach the drywall? I know furring strips and then drywall would probably be the safest bet, but I'd rather try to keep as much ceiling height as possible.


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    I know removing the plaster entirely would also be a good option, but I'm not interested in the gigantic mess it would create. :)
    – BenCJ
    Commented Jan 22, 2020 at 18:15
  • When you say it is sagging, is top coat of the plaster separating from the scratch-coat or is the entire thickness of the plaster drooping? If you aren't sure, you might need to poke at it will a screw driver or knife and open the surface to see what's moved.
    – JimmyJames
    Commented Jan 22, 2020 at 18:32
  • JimmyJames - It's sagging because a lot of the ceiling has broken off from the keys.
    – BenCJ
    Commented Jan 22, 2020 at 18:38
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    @BenCJ Assuming the non-repaired ceiling collapses into the new false ceiling you're imagining (or just shifts possibly impacting the false ceiling), how would the subsequent repair be less of a mess?
    – Edwin Buck
    Commented Jan 22, 2020 at 20:05
  • Just a quick note: Definitely consider renting a panel lift/panel jack. MUCH easier than the old solution of multiple people trying to lift and place T props under the ceiling panel so you can drive the fasteners.
    – keshlam
    Commented Jun 22, 2023 at 13:36

3 Answers 3


Adding a layer of gypsum board over your existing plaster will only be as level as the existing plaster. First, make sure it’s acceptable.

Second, you may want to test it to make sure it’s not asbestos. If it is, there’s no special reason to remove it, but you’ll want to be extra careful working in that room until it’s “encapsulated” with the new layer of gypsum board.

Depending on the existing ceiling plaster’s condition, anchoring to the plaster could be a problem. Finding the support spacings above and anchoring into them seems safer. AND you’ll probably want 5/8” thick gypsum board in lieu of 1/2”...1/2” tends to sag over time if the supports are more than 12” on center.

  • This is what I was thinking too. Screws every 16 inches on every joist. If the plaster is breaking away, it's useless for securing the wallboard.
    – JimmyJames
    Commented Jan 22, 2020 at 19:41
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    Above it isn't flat and is having support issues. I wouldn't add weight to it. Even if it looked good for a couple weeks or months, having it fail at any future point is not worth it. If the drywall bulges and seams crack what do you do? Start over?
    – DMoore
    Commented Jan 22, 2020 at 19:55

The plaster is sagging probably due to issues with some of the lathe boards above it. Those need to be repaired.

If you have access above this you could just knock these totally out and reframe with 2x4s. This would probably be the quickest way.

As far as mess... You are thinking about this wrong. Demoing might be a mess. Sanding the mud for the new drywall will be 10 times worse for your house.

My advice is knock out the ceiling. (this will take minutes) Then reframe and then add drywall. This space will have to be totally emptied out. If you are quick you can get drywall up with first coat of mud in day 1. Day 2 you can add second - final set of mud (if you are really good). This will take at least two days to dry. Day 4 you are sanding. That is best case scenario. Room will have to be emptied and doorways will have to be tarped off from rest of the house.

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    And you keep your headroom too with the slats coming out.
    – CrossRoads
    Commented Jan 22, 2020 at 18:38
  • Pulling the plaster down might not take that long but collecting it and removing it is could be a pretty big job depending on the size of the room and what floor the room is on.
    – JimmyJames
    Commented Jan 22, 2020 at 19:46
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    @JimmyJames - No you throw the big pieces in large trashbags or a bin. I can do demo and take out large pieces of a large family room in an hour with me and a helper. You keep the mess there. That way when you are dropping mud all over it is easy to clean up because it isn't directly on the plastic or whatever you are using to cover. Do the final cleanup after the last sanding day. Sand will be in the air for about half a day (after it is but not as bad) - this is when you do final cleanup. No matter the solution it's a mess.
    – DMoore
    Commented Jan 22, 2020 at 19:53
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    @DMoore I believe you but I think for someone who doesn't do this regularly, it can be a little overwhelming as in if you don't have the equipment like a trailer or even a pickup truck, etc. I has a 8X10 bathroom demoed and 4 tons of material came out. I started off thinking I could do it on my own but each contractor bag of lath-board must have weighed 50-75 lbs. Doable but probably not on the timeline you could do it.
    – JimmyJames
    Commented Jan 22, 2020 at 20:02

I had a similar issue with my brother-in-laws house. It was old and poorly constructed. The ceiling was sagging badly in the middle of the living room, it was almost 3" lower in the middle than the walls!!! Turned out that the joists were terribly over-spanned...like 20' 2x4s. Earlier, he and his wife, not knowing better used the attic space as storage. Then he added a layer of sheetrock. I ended up tearing out the ceiling joists completely and replace with 2x8s. (there were no trusses). But we did some tie-ins to the rafters to support the roof. Needless to say this was a major patch job to make the house last a bit longer for them. The house wasn't worth major repairs, in reality it's a tear down.

Sorry for such a long explanation, but the bottom line is be sure your ceiling joist/truss/attic structure is solid before making more cosmetic repairs.

I like Dmoore's suggestion. His timeline is for professionals who are good at it...probably a crew as well, not just a single DIY'er! Still, I think his approach is solid: Get that old stuff outta there and evaluate the structure. Maybe add insulation if needed at the same time.

You'll want to be sure you're screwing the sheetrock to the joists, not just lathe.

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