I’ve got a couple of clients that are asking me about fixing some flaking plaster walls.
I’ve done plenty of drywall work, but not messed with plaster any yet. Any special tricks to working with plaster? Can you just take regular sheet rock mud / tape to fix defects?
Another question that has pondered me is what’s so special about plaster walls anyway? They seem to be preferred by some, but I don’t see much difference estetically between plaster and drywall, once there painted.
I’m guessing maybe the paper texture of gyp board shows if you look at it really closely as opposed to plaster. If that’s the case, could you skim an entire drywall surface with mud before you paint to get a “plaster” effect?
Replies
"If that's the case, could you skim an entire drywall surface with mud before you paint to get a "plaster" effect?"
do a search on D-Mix here.
bobl Volo, non valeo
Baloney detecter
Plaster makes for a very quiet house. On the downside, I've got two rental properties that have plaster, and I always warn the new tenants not to try to drive a nail in the wall to hang a picture. Guaranteed to knock out a chip as big as my thumb, every time !
Greg
I'm still learning after 38 years drywalling, but here's a couple of tricks:
Carefull scrape off the loose top. Sometimes I have made plaster washers by cutting a piece of strap iron and hitting it in the center with a ball peen or cat's paw then screwed it at strategic points into the wood lath (carefully drill for the screw).
Use fibreglass tape over major cracks - just fill minor ones.
I usually use all purpose mud (sticks better) and add some soap (about a golf ball glump in a 5 gal bucket. That makes it smoother and stick better (surface tension or something).
Another trick. Sometimes what I am needing is, say a 1/4 inch thick piece installed, say 12 in by 12 inches. I lay a piece of drywall on a table face down, saw across it at the correct depth with a little battery saw and thin it to what I need. It needs careful support to do this. Then I butter the back and butter the wall and install it using screws at the corners to temporarily hold. Then tape around the crack.
There's nothing really special about fixing plaster using drywall methods.
By the way, I have seen the time that a large area of "topping" was off on a ceiling (from a leak). It worked well there to prime with KILZ (old style, oil) then trowel on the lightweight mud.
Probably some others have other techniques. I'll be watching this one too.
I second the D mix search.
Simple, quick, easy. Fun
GoodLuck
Zinsser makes a pretty good ready mixed plaster patching compound. It will work for small holes and cracks. I haven't tried it on a larger shallow area yet, though I have patched a 3" by 5" hole. The trick there is to get a good bond. Be sure to pre-wet the area.
Or you can patch using real plaster and lime. Again, make sure that if there is any paint that you add a bonding agent of some type.
Fender washers also work as plaster washers. But soemtimes the wood lath will split. It is usually very dry. Sometimes it helps to use a spade bit to counter sink the washer.
If you use drywall compound, it will not be as hard as plaster, and you will have to sand.
Plaster is harder than drywall, and does not have the flatness of drywall.
D-mix, while I'm sure is a great product, is not a plaster patch.
If you decide to spade bit to seat a plaster washer in the plaster make sure it is a flat blade without the two teeth on the outside of the paddle and don't drill in any farther than part way thru the topcoat to maximize the strength of the washer.
Also a further boring for the depth of the washer screw head where it mates with the plaster is advisable to help lessen the protruding height of the screw.
What you're seeking is the flattest area for the washer so less build up of whatever compound you will be using. Screwing in too tight runs the risk of causing the edge of the washer to curl out above the plaster surface.
A fairly meticulous procedure and only worth doing in small patch repair jobs. Much too time consuming for large cracking walls and ceilings.
In that case just screw them in and punt.
'Nemo me impune lacesset'No one will provoke me with impunity
Edited 1/19/2006 2:32 pm ET by razzman
We all know how hard plaster is, and how abrasive it is if you try and scrape any part of it. Started using a carbide scraper and it works fantastic. It's quite easy to scrape the area around a crack prior to taping so the tape repair isn't sticking out from the wall so far.
A friend in comercial construction says they duplicate plaster walls by spraying a highbuild primer quickly followed by a light coating of sand from a sand-blaster gun.
On smaller repairs I've primered, then applied a healthy coat of paint to which sand is applied (dabbed) in small quanitities with the tip of a paintbrush. The brush picks up a little paint and a little sand. It takes the right coarseness of sand and we've resorted to sifting regular sand when needed. Sometimes the sand they sell as a paint additive for traction areas is just right for small particles. A couple more coats of paint to cover the sand and help it match the wall and you're done.
You've gotten some good advice so far. Plaster walls are the norm in the homes I work in, here's what I do.
As with any repair, you need to determine why the plaster failed in the first place and fix that.
If it's finish coat failure, look for moisture within the wall or ceiling, if the crack extends into the base coat check the surrounding plaster to make sure it's still keyed to the lath. Break out anything that has lost it's key. You can fill to within an 1/8" or so with dry wall back buttered with durabond and screwed to the lath.
If the plaster is just a veneer over blueboard, sink a few screws into the framing on either side of the the crack just like you would if it were a dry wall repair.
I use durabond and easysand setting compounds for repairs as I'm more confident in the bond to various surfaces and the open time better suits my speed/skill level.
The awful thing is that beauty is mysterious as well as terrible. God and the devil are fighting there, and the battlefield is the heart of man.
- Fyodor Dostoyevski
another tip is to add a big splash of milk or vinegar to the platser mix. It gives you a lot more working time.
The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..I honor the place in you where the entire universe resides, I honor the place in you of love, of light, of truth, of peace. I honor the place within you where if you are in that place in you and I am in that place in me, there is only one of us.
I know plenty of people say to add vinegar to retard the setting time of plaster, but me, I wouldn't put vinegar or any other acid in a substance whose prime component is lime. Just seems like a problem in the making.A tiny dash of cream of tartar will extend working time about an hour.
I've heard vinegar...haven't tried it but I "always" use milk and it works.The secret of Zen in two words is, "Not always so"!
When we meet, we say, Namaste'..it means..I honor the place in you where the entire universe resides, I honor the place in you of love, of light, of truth, of peace. I honor the place within you where if you are in that place in you and I am in that place in me, there is only one of us.
I've done literally miles of cracks to save the old plaster in my house. The one thing I haven't heard mentioned in this discussion is the critical importance of using Hy-Bond, painted over the crack repair area (and allowed to dry) before any plaster / mud is put on.
It smells and acts like Elmer's glue, and evidently re-emulsifies when you put new plaster on it, and keeps the old dry plaster from sucking all the new moisture out, and making a bad bond. It also seems to help anchor calcimine paint.
I've also used the product HD sells for coating concrete before new concrete is placed against it. Seems to work the same.
Forrest
Been so busy I havn't had a chance to set down at the computer for a couple of days.
Thanks to all for the information. I'll be working on that house next week.
Well, I didn't mention Hy-Bond, or any other particular product because I never know what is available in some other area.But I did mention bonding agent several times.
Dap plaster wall repair comes in 25 lb sacks. It has a retarder in it for a 3 hr working time.
"flaking plaster walls."
Implies water damage (old or active), or some sort of coating failure.
Need to get the loose coating off.
Worst case it's calcimine, which has a lousy bond, and will come off in big sheets if it gets wet.
As for plaster in general, the stuff makes for stiffer walls, and and a completely different texture from drywall. Nowadays you can emulate the old plaster with blueboad & a veneer coat.