Suggestions for Plaster Repair?

12 years ago

I recently purchased a 1920's home in central Massachusetts and am getting to work on renovating. One of my first projects was to redo an upstairs bedroom that had some badly peeling wallpaper. After stripping off the wallpaper (which took all of 15 minutes with no tools, very poorly applied), I was left with a very rough plaster surface which seemed sound, if not the most attractive texture. I decided to try my hand at skim coating with finish plaster on one of the walls to smooth it out. That went fairly well so I made the decision to go ahead and start removing molding to do a proper job the of the whole room. Here comes my problem. I got the lower molding off of one of the windows to discover that the plaster was not at all adhered to the lath behind. There's a good 1/8" gap between. The edge of the plaster under the sill was dry and crumbling to boot. Some experimental pushes against the walls in other parts of the room seem to indicate that I may have the same issue throughout the room.

So, obviously I need to deal with the crumbling plaster underneath the window, but I'm wondering how much of an issue the potentially separated, but still intact plaster is in the rest of the room. I hate to tear out perfectly good walls if it's not entirely necessary. Anyone out there have any advice?

Comments (8)

PRO
Christopher Nelson Wallcovering and Painting
12 years ago
I would leave it alone until it is absolutly necessary to repair. It might look OK for another 50 years.
stash-hdy
12 years ago
Redoing plaster is not a homeowner task so I would have a professional come in and access the situation.
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brickeyee
12 years ago
"Redoing plaster is not a homeowner task so I would have a professional come in and access the situation."

Except in many places there is no one who does plaster or plaster repair.
sierraeast
12 years ago
Sounds like your window at one time had a leak causing the weak area in your plaster. Mass. has tons of plaster pros. Your best bet to get a reputable one would be to go talk to a supplier of masonry/plaster products and get referalls. Ask friends, family, co-workers for referalls as well.
graywings123
12 years ago
Try posting your question the Old House forum.

Here is a link that might be useful: Old House Forum
alexrander
12 years ago
Unless it's on the ceiling, I would not worry about it. Patch or fill in with 45 minute joint compound, or plaster of Paris. When mixing - always use a clean container. Old joint compound mixed with the fresh causes the fresh mix to set up faster. Yes the the plaster should be stuck to the lathing, and in fact it's hard to imagine how it could not be, considering how it's applied.. The lathing is also there just to stop the plaster from filling up the entire void between the wall studs.

Ceilings would be my only concern and you would notice it if your plaster or lath was sagging. And that's repairable too with large washers bolted into the lathing or screwing the lathing back into the joist.
brickeyee
12 years ago
"plaster of Paris"

Do not eve try plaster of Paris.

It hardens way to fast to be worked unless you add a LOT of retarder.

Use Easysand or if you are experienced Durabond.

Durabond is about as hard as plaster and does NOT sand well (just like real plaster).

Easysand can be sanded.
mrblandings
12 years ago
Plaster washers are designed for reattaching plaster to lath. You screw the washer in just enough to create an indentation in the plaster, which you then cover over with your patching compound. I have seen plaster washers in some hardware stores but otherwise can be mail ordered.

Here is a link that might be useful: plaster washers