Sagging but sound plaster ceiling

We bought an 1895 house last year in good condition and have been doing minor repairs bit by bit. The only bathroom is upstairs and had a significant moisture problem due to lack of ventilation, resulting in peeling paint. We finally installed a bathroom fan that seems to have solved the moisture problem, so we started scraping the peeling paint to be able to repaint the walls and ceiling.

Under the paint was a thick layer of some sort of compound, that came free from the plaster when we started scraping the paint. The plaster underneath looks to be in good shape, with no big cracks or holes, no signs of repairs, and no loose areas, so we were pretty happy.

When we got to the ceiling, however, ridges started appearing in the plaster where the keys are sagging from gravity. When I press on the plaster, it doesn't feel loose and doesn't make any crunching sounds, and isn't cracked anywhere. It feel secure and solid, but unable to compete with gravity.

Can we fill in the spaces between the ridges, as the previous owners did? If so, what is the best product to use? Does the plaster need to be repaired/reaffixed? Is this project something we could probably do ourselves, or is it best to call in an expert? We have experience with minor home repairs and have done drywall and foundation patching-would this be similar? We thought this would be a simple scrape bad paint job-should've known better with our old house!

Sorry I couldn't figure our how to rotate the photo, but if you turn your head, you can see the ridges from every key, every couple inches on the slanted ceiling and the flat ceiling (we have a 1 1/2 story home).

Here's a closer view of the ridges in the plaster.

I think your ceiling was never finished at the time. see scratch coat samples here
http://inspectapedia.com/interiors/Plaster_Ceilings.htm

Tellebot said:

Sorry I couldn't figure our how to rotate the photo, but if you turn your head, you can see the ridges from every key, every couple inches on the slanted ceiling and the flat ceiling (we have a 1 1/2 story home).

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Rotated it for you.

No way would I have the patience to deal with that mess.
I'd just go over it with new drywall or tare it down and redrywall.

nealtw said:

I think your ceiling was never finished at the time. see scratch coat samples here
http://inspectapedia.com/interiors/Plaster_Ceilings.htm

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I think you might be right-I hadn't considered that possibility, but it would explain why it looks like it's sagging but feels so secure. What would the best course of action be?

Here's a cross section view of the lath and plaster where the medicine cabinet goes, if that's useful to see. It's sideways again-is there a way I can rotate images myself, and save the moderators that step?

joecaption said:

No way would I have the patience to deal with that mess.
I'd just go over it with new drywall or tare it down and redrywall.

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I kind of feel the same way, but would like to preserve as many of the old details in my home as possible. If the plaster is as solid as it seems to be, I'd rather find a way to keep it, as long as it isn't prohibitively difficult or expensive.

There are sites that talk about old proceedures but I think you should think about insulation and free air venting above that. Modern construction like this would have 9" between ceiling and roof sheeting.
[ame]https://www.youtube.com/watch?v=8iUcenpHg84[/ame]

nealtw said:

There are sites that talk about old proceedures but I think you should think about insulation and free air venting above that. Modern construction like this would have 9" between ceiling and roof sheeting.
https://www.youtube.com/watch?v=8iUcenpHg84

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That video makes it look so easy!

The slanted part of the ceiling is right under the roof, but the majority of the ceiling is flat, and there's a crawl space above that with blown in insulation.

Just the fact that there is plaster, suggests that insulation above the ceiling on the slope will be min. at best. This would add to the condensation problem in the room and should be considered as this would be the time to tear it down add thickness to the cavity and insulation and new drywall. Just hate to see you finish the plaster and then say should have done it.

Thanks again for your help. I decided it wasn't in the budget to do as you suggested and add to the cavity and insulation at this time. I ended up using a product called Plaster Magic for some areas where we accidentally pulled some plaster down and where there were cracks to reuse cure the plaster to . None were significant, but I figured I might as well do all I could to keep the plaster secure and crack-free while it was exposed. 5 coats of all-purpose joint compound + 2 coats of topping compound, and it is starting to look smooth and modern. Hopefully this was an okay decision, and will last a while!

Can I rotate photos somehow??? They always post sideways!

If you down load the photo to your computer you can rotate it there and then post it.
Or hold the camera sideways.
The plaster looks good.

I'm ready to see the end of this project. While not particularly difficult, all the coats of mud were time-consuming and tedious, especially since it added significantly more time to a simple repainting job. And with two jobs and a toddler, I haven't been able to work on it every day, so it feels like it's dragging on. Now that I've spent so much time trying to make these walls perfect, I've started seeing imperfections I've never noticed in other walls in our house!

Tellebot said:

I'm ready to see the end of this project. While not particularly difficult, all the coats of mud were time-consuming and tedious, especially since it added significantly more time to a simple repainting job. And with two jobs and a toddler, I haven't been able to work on it every day, so it feels like it's dragging on. Now that I've spent so much time trying to make these walls perfect, I've started seeing imperfections I've never noticed in other walls in our house!

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perfection is unattainable

chrisn said:

perfection is unattainable

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Sad, but true. But I'm trying to get as close as possible!

The imperfection in plaster walls is the character that some people love.

Finished at the end of January. Thought you all might like to see how it turned out. Not effect by a long shot, but I think it looks pretty good, and a million times better than before!

Looks great nice job.