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sharp 10-17-2009 09:32 PM

plaster / drywall
I have a sag in the ceiling in the living room. The room is 11' X 19'. The walls and ceiling are plaster with an original texture. To fix the ceiling should I, or could I, remove the entire ceiling and replace with drywall leaving the walls plaster. If I do this would I be able to match the texture. I don't have any photos at the moment but will post some soon.
Price is a concern on the project, and I think the sag is too big of an area for a patch to work.

Gary in WA 10-17-2009 10:50 PM

1. Need the span of the joists. (how long in feet).

2. Need the size of the lumber - 2x4, 2x6, etc.

3. Is there living space above?

4. Should you, yes if over-spanned. Could you, I don't know what your abilities are?

5. Does it match one of these?
Be safe, Gary

user1007 10-18-2009 06:30 AM

Here is another approach. The plaster repair washers and buttons might work too. Only if the lathe or other supporting structure is intact though. Do you know what is causing the plaster to sag? If there is condensation or water damage you should probably take it down and drywall or replaster as the plaster that is up there will have been compromised.

As for texturing it will depend on your skill and what sort of pattern you need to create. There are all sorts of tools that might help you out with a ceiling. Some times it just takes some practice, experimentation and getting accustomed to using powdered mud so you can control thickness of your final coats of texturing materials.

bjbatlanta 10-18-2009 03:18 PM

Sounds like the ceiling needs to be replaced (hard to say for sure sight-unseen). Matching the existing texture would be the problem (if you do replace just the ceiling) and make a smooth transition/blend with the existing on the walls. I would add crown mold to allow a break between the two so the blending/matching of texture isn't so critical. You could even go with a different texture on the ceiling or leave it smooth......

sharp 10-19-2009 10:49 PM

Thanks. Still trying to figure the extent of the work I want to do here.

Allison1888 11-04-2009 10:48 AM

drywall or plaster
I would take the plaster down and use drywall, not worrying about adding a finish. I love plaster, but it's not worth it to spend hours ($$$) fixing the ceiling when you or a painter can replace it pretty quickly and inexpensively.

Skuce 11-04-2009 11:26 AM

Hold old is the home? The Plaster that is it just a decorative plaster (ie: 1960's+) or is it a traditional plaster/lath combo (ie: pre 1930)

sharp 11-11-2009 12:28 AM

it was built in 1930, plaster and lathe.

Skuce 11-12-2009 11:28 AM

Ok. 2 routes.

Remove the sag and replace with new Lime Plaster. Has to be Lime or it will crack at the edges and also look like crap. (I'll get more into this in a sec)


Use the stainless plaster washers with stainless deck screws to pull the plaster back up to the lathe in the sagged region. Then scuff sand the whole area and skim parge with a gypsum based product like Durabond 90.
Use a wet whitewash brush on the setting gypsum plaster to duplicate the old hand wrought plaster finish. DO NOT sand level. Use only trowels and wet brushes. You'll get the same texture back (if it's a flat ceiling)

Second route is to drop the whole section of sagged plaster to the floor. Be very careful to only drop the damaged plaster and to not break the keys in the surrounding plaster that is still good.
-Clean all the lath with a brush to get as much dust off.
-Clean out broken keys that are still in the lath gaps.
-Back bevel the surrounding good plaster so that the new plaster locks into it.
-water down the lath with a spray bottle to hydrate it
-Mix up your brown coat of LIME plaster that you will be putting on. Hydrated Lime to fine River Sand - Mix 2.5 parts Lime to 1 part sand
-Only add water the first time you mix it up. Don't add water again later if it starts drying out when you are using it. That's called Re-tempering.
-Parge on the the first coat onto the wet lath.
-Force the plaster in to make all brand new keys in the lath.
-Diamond scratch to give the next layer a tooth to bite.
-Let that be for about 4 days - Lime ONLY cures by carbonation. It has to be exposed to the air to harden. Lime = Calcium Hydroxide. You want it to become Calcium Carbonate.
-Lightly mist 2-3 times a day.
-Mist just before next coat
-Parge on the next coat of Lime plaster. Same mix as the first
-Diamond scratch again or use a stiff bristle brush to make a tooth.
-Let cure 4 days with the misting.
-Mix up the final Lime plaster coat. 3 to 3.5 parts Lime to 1 part River Sand.
-Mist/Hydrate previous layer
-Parge on final plaster coat. Making it flush to the surrounding plaster.
-Use a wet white wash brush to feather the plaster and texture it to match the surrounding plaster.
-Let cure for a week - Misting 2-3 times a day for the first 4 days.
-You can paint with a Latex in about a month, Oil is about a year. Oil seals out the air too much for carbonation but the Latex is more permeable.

You just restored a tradtional plaster ceiling that matches the original in almost every way.

Gary in WA 11-12-2009 12:20 PM

Is there extra weight up there?

Are the ceiling/floor joists compromised due to knots or splits from the original installation?

Are the joists over-spanned and just sagging over time because they are?

Is the plaster sagging or the joists with plaster? Find the source of the sag before a band-aid or complete redo. You will have a nicer looking sagging ceiling. (hence my previous questions....)
Be safe, Gary

sharp 11-18-2009 10:10 PM

Thanks for the replies. I decided to get rid of the plaster and sheet rock everything. Hope I didn't make a mistake.

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