Remodeling the kitchen. (oh joy). Removed formica backsplash behind sink. Peeled, scraped old adhesive. Have some big areas (2 to 3 inches by 3 to 6 inches) where the finish coat of plaster cane away from concrete? layer, which is in turn over lath. Concrete not damaged. Finish layer of plaster appears to be about 1/32" to 1/16" thick. How should these be repaired? Step by step, with products, please (sealers, primers, bonding agents, etc. Brand names very helpful.). The big box stores nearby aren't much help, as they gave different advice. Hoping someone here has actually done this. I'm mostly worried about the adhesion. I also would like to know if I have to scrape all the old paint, or is there a sealer, so the plaster repair will stick at the edges? The old paint does not feather worth a damn. Finish work, I am very good at. (body work skills).
OT: fixing plaster wall
Aug 14, 2013
4 Replies
Clean edges and surfaces and re-plaster.
Mart> Remodeling the kitchen. (oh joy). Removed formica backsplash behind
Use a semi-stiff brush to clean all the loose stuff from around the edges. Wet the whole area with a sponge or paintbrush. Mix up some plaster of pari s and go to it. You do have to work pretty fast, as the stuff sets up quick ly (less than ten minutes in my experience). You need to have a large, clea n trowel to get it smooth. Your area is not so big - I did a section of wal l about two feet by three feet, and it came out pretty good.
Actually, if you're only dealing with a 1/16" thickness, you could easily d o this with joint compound, which is much more forgiving, and you can re-we t it after it dries if you want to rework it, or you can just build it up, in one or two coats (feather it out with an 8" or larger taping knife), and sand it down.
_Way_ too quickly for me. I use "patching plaster". Much better pot life, which means more workable. I've used probably 100 lbs of the stuff over the years.
For an even-nicer job, use "veneer plaster". It's the stuff that's used over blue board for a pseudo-plaster job. Has a very plastic consistency that allows it to smooth nicely. But you probably won't find it in less than 25 lb size.
Also, I use a spritzer to wetting the old plaster - more control. It is essential that the old plaster be wetted - otherwise it will draw out the water from the new plaster before it can hydrate. Don'r worry about using too much.
Your small sized patches will make it easy to get flat/smooth. Just use a trowel or large putty knife that will span the patch, riding on the old plaster.
Bob
An almost invisible plaster patch can be made using a 50/50 mixture of Plaster of Paris and Poly-Filla. Doesn't set as fast as plaster of paris, and has the celulose fiber to toughen the plaster. Lots of early plaster had horse-hair in it to give it strength.. My brother has done a lot of plaster repairs in his roughly 100 year old house using this mixture over the lat 30 years, and you cannot see any of the patches
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