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What kind of joint compound to cover plaster washers in old wall?

last year

We have original plaster walls in our 1915 home, and after some renovations, one wall has a bunch of loose keys. We've successfully used plaster washers to secure it and now need to cover the washers, but I'm reading mixed things on what kind of patching plaster/joint compound to use over the washers to ensure it adheres well to the original plaster.

Anyone have any experience with this and have a suggested brand or product? I know we first need to cover the washers with fiberglass mesh tape, which we have. After that--patching plaster? Old school plaster of paris? Drywall joint compound? Something else entirely? Thanks!

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Comments (6)

Debbie Downer
last year
With plaster repair (as with a lot of things related to old houses) there's a variety of opinons. Ive not had much luck with mesh tape and instead used a bonding agent which helps adhere the new plaster to the old (per advice from my plaster guru many yrs ago). Used mostly EZ-Sand 90 for surface skim coat kinds of jobs and Quikrete Bonding Adhesive (Plaster-weld or anything similar) . You didnt ask about cracks or deep repairs down to the lath but for that you would use real old school 2-coat plaster (obtainable from a specialty store, not big box)) with EZ-Sand as the top coat.
PRO
Ripped Jeans Construction
last year
Agreed with Debbie - as a non-pro, your best bet is a sandable setting compound. EZ-sand or Durabond, depending on how much you hate sanding :)
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artemis78
Original Author
last year
Thanks! We ended up just getting patching plaster at the recommendation of our local hardware store, but aren't having much luck with the mesh, so depending on how well the plaster adheres on its own, may need to look for the Durabond or similar.
Debbie Downer
last year
last modified: last year
Try the bonding agent - adheres old plaster to new and gives some added assurance against re-cracking. My plaster guru made the good point that if its going to re-crack, then it will do so whether or not there is mesh over it and then its a major pita to get it off. I can testify to that - my house's PO did mesh tape a and then globbed finish plaster over it. It looked like giant scabs all over the wall, didnt prevent re-cracking, and taking it off added double the time to do the repairs. Mesh tape was made for drywall joints where theres that indentation that the tape sits in. Where she put big sheets of it over plaster washers, whole sheets failed and came off as a big chunk. I think not enough plaster gets through those tiny holes to really be able to adhere firmly to the old plaster.
artemis78
Original Author
last year
Thanks! We ended up skipping the tape for the plaster washers and just using a metal mesh tape in an area where the plaster had come off entirely, and then did multiple layers of patching plaster over several days. Sanding and priming it tonight. Looks decent enough, though can't say how well it will hold up long-term...but at least it's no longer loose or falling off the wall in chunks! If it doesn't hold we will probably just have our plaster guys come in, take it down to the lathe, and redo the whole wall properly, but I'll cross that bridge if we get to it. Thank you for the help!
HU-723692230
last year
You need a bonding agent (like plaster weld) before putting on the patching coat. Unfortunately the mesh won't solve the bonding problem (it helps prevent cracks). It will stick for a time being. If it comes off, use a bonding agent, don't redo the plaster with drywall. Its a mess and expensive.

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