I’d like to test an idea that’s been bugging me for a while - how to bring back old plasterwork without having to gut the whole thing, lath included, and replace it with wallboard. I propose skim coating the surface with say, 45-minute quickset, using a trowel with deep triangular notches. Then after drying go over it with a sanding screen stuck to as large a base as practical, using a pole attached to a swivel joint. The idea would be to achieve a flat surface by sanding down the peaks of the V-grooves, a much faster process than sanding the new plaster over its entire area, which would just reproduce the waviness of the original wall. Then follow up by filling the valleys with a harder layer, say, of plaster of Paris (poP), using the sanded peaks to guide the trowel and produce the finished surface. Final sanding would be needed to smooth out the poP (which expands) and minor nibs. A wet rubber float could be used before the poP sets up. I’d think an average room could be done in a day if the ceilings are no more than 8’. Applying a 3/8" - 1/2" layer might mean not having to disturb existing door & window trim and wall plates. Unsound areas of old plaster could be bored with holes, through which a compound could be injected that would readhere the plaster to the lath. The alternative would be a zillion-dollar project, producing an unholy mess.
Has anyone tried this?
Moving from GQ to The Barn house at request of the OP.
Colibri
General Questions Moderator
I’m not sure what you’re trying to do but I had a house which had drywall just placed over the old plaster & lathe without removing anything and it was just fine.
An old trick i used in a 1919 house;
if the plaster is, overall, sound and well-secured to the wall, you can attach 1/8’ masonite, rough side out, over the entire wall, then skim coat. The result is indistinguishable from plaster, and you only lose 1/8’ in depth of the woodwork.
We did this as well in the kitchen - worked just fine. We took out the cabinets to refinish them, and replaced the trim, so if you’re trying to match up with existing woodwork, that may be out.
I did a ton or research re: re-plastering, and it was far too much for us to handle…
ETA: replacing the plaster might not be as bad as you think. Lots of demo, but it goes fast, and if you can contain the dust, clean-up isn’t that bad.
One would assume you have cracking issues. If the wall is structurally sound and not falling apart, take a (hmm I don’t know the name of the tool, it’s a triangular scraper painters use) and pull it down the crack, widening it/ deepening it. I have seen plastermen just fill it and sand it at this point, but I would consider using a mesh tape (not paper sheetrock tape, the mesh kind) to prevent recracking. You could use sheetrock mud instead of plaster with no problem. The idea is to rebond the fractured structure of the underlying browncoat.
I’m not a plasterman (tile/stone) but I am pretty familiar with plaster and lathe as I live in Charleston SC. I have an old book from my dead master “Plastering and Related Subjects” from the 1920’s Chicago Plasterers Union showing how to make egg and dart crown moulding, fluted columns, groin ceilings, all types of arches, poured marble, lathing techniques, etc. That’s the repair method in the book as well (minus the tape).
Or, cover it with sheetrock (wallboard). Or wallpaper. Or “stucco” it.
Good Luck