Hi, I'm wondering how to patch plaster walls..it will be pretty much impossible to cut the hole to a square, the plaster behind the wall is crumbling, and there is lathe behind the plaster..can I just buy plaster and spread it over the hole evenly? Or how exactly do I do this? Thank you so much for your help!

real classic plaster has several layers. the "hair" layer with horsehair in it is applied liberally over the lath, so there are clumps behind the lath anchoring it in place. this is scored horizontally, also called the "scratch coat," to provide tooth for the next layer(s). a cover coat goes on next, and if it was concreted or coarse, a third fine layer of lime plaster goes on for the smooth final finish.

most repairs now will have wallboard put over the lath, screwed into the studs, and filled to level with wallboard compound. it won't look "right" in there, because real plastered walls typically have bumps from fine aggregate.

if you want to do it the old time way, a real serious paint store (not a home center) should have small boxes of plaster. you'll have to ask to get them, they won't be up front where the high margin stuff is sold.

it is borderline possible to patch using drywall compound in place of plaster, but it will crack and shrink like nobody's business... you're going to be at it on and off for months. this sort of result is an indication that you are doing it very wrong. trust me, I know

This message has been edited. Last edited by: swschrad,

thank you! I will definitely not use the drywall stuff, that is why I asked about patching with plaster..I will go and ask them thank u again!!

He's a piece from This Old House on patching real plaster.

http://www.thisoldhouse.com/to...e/0,,1172537,00.html