I started repairing some gaping holes in the ceilings and walls, tacking up wire mesh to the lath, and then applying a rough mix of plaster and cement or gypsum and plaster.

Now I'm applying finishing coats of just plaster, feathering it out as far as I can, and wondering if there are better methods. The finishing coats have come away from the walls in places and I've had to re-do a couple of areas more than once.

The instructions on the bag of plaster say to apply it to a dry surface. I found it adheres better if I make the surface damp first. Someone mentioned "bonding agents" in another post. Any suggestions?

I'm almost done, but for the future, what are the best methods for repairing plaster and lath walls and for applying skim coats to walls that are cracked and rough? I still need to apply some skim coats.

Also, I'm almost at the stage where I need to sand the patches smooth. How long do I have to wait for the plaster to dry before sanding? The holes varied in size from a foot and a half across to three inches around and I've built up the walls almost an inch in places that were uneven.

AskMeHelpDesk is a great site. Thank you all for all the advice you give.

skiberger

So far it sounds like your doing a good job. One thing you may consider if the walls are that bad maybe cover over them with 1/4-3/8" drywall.

If your skimming the walls, maybe use spakle instead of plaster. Its easier to work with. Just make sure all the cracks are meshed taped.

For sanding, as soon as it dries if you can if not plaster is very tough to sand.

splanky

Thanks, Skiberger.

I had an opportunity to watch a guy by the name of Miro work yesterday. He did incredibly perfect walls, corners and curved archways.

Prepping: He didn't bother chipping out the cracks and used mesh tape to cover them, like you said, careful not to wrap the tape around a corner, but to apply two pieces instead. He didn't dampen the walls beforehand.

Mix: He took about 1 part water, added roughly 2 parts plaster to it, letting the bubbles rise up as much as possible, and then mixed in about 2 parts of joint compound until the consistency was uniform. He did it all by eye and really couldn't give me measurements.

Application: When he applied the mixture to the walls, he was able to smooth it out very far and very flat using a 10" flat-edged trowel - the kind shaped like a ping pong paddle with the top half cut off. He use a smaller, similarly shaped trowel to apply an equal amount or bead along the entire edge of the wider trowel. He was careful to put on the trowel only as much mixture or as wide a bead as he needed to cover the particular area he was covering with that swipe.

He was able to work with the mixture much, much longer than one can work with straight plaster, but it dried quickly enough for him to apply 4 coats to a fairly large area in just a few hours. I think the first and second coats were thicker than the third and fourth ones were. Between the second and third coats he went to lunch for an hour "to let it dry".

For the fourth and final coat he used joint compound only, which he added water to first, adding it directly to the bucket of joint compound. He said it got a bit dry while he was dipping into the bucket with the cover being loose. I also think he added the water to help keep the joint compound fresh for the next time he uses it. The fourth coat went on thinnest.

The surface is so smooth and flat now that it won't hardly need any sanding at all. Also, the joint compound doesn't seem to dry as hard as the plaster. I'm going to try Miro's method, going over the plaster I applied before. It will cut down a lot on the sanding, which I plan to do as soon as it's dry.