How do I remove or smooth old textured plaster?
I live in a 50 year old ranch. The walls throughout the house are what looks like 3/8ths drywall with a layer of plaster over that. A few years ago I replaced the main electric panel, and had to cut in some areas to run wiring, and removed the old panel. The new panel is in the stud bay right next to the old one. I’ve patched the larger holes with drywall and would like to finish the walls and paint. This area is the stairwell going to the basement. The problem is that the original walls were coated with some sort of texture. It looks as though someone went over the whole thing with runny plaster. I would rather have smooth walls, and an article in FHB caught my attention. The article is “Make Old Walls Smooth and Sound” by Tim Leahy. The author creates a new finish on old walls by covering the entire surface with fiberglass mesh and then applies a few coats of joint compound. The texture I have on the walls isn’t really deep so I thought I could scrape off the high spots, apply the mesh, and with a few coats of compound, have smooth walls. I would like to ask if anyone has had experience with this method and if it would work well for my situation? If not, would I be able to apply some sort of texture over the old and new sections to make everything uniform?
Replies
You don't need to apply mesh
You don't need to apply mesh to the walls, unless the walls are full of cracks and loose plaster...which, in your case, does not seem to be the problem. Simply skim coat the wall using joint compound. Use the 90 minute mix that you mix yourself. Use a 12 inch long plaster trowel, or if you perfer, use a 12 or 14 inch drywall knife. Coat it lightly and let dry. After this coat has dried, apply another coat using premixed joint compound. Thin it out slightly and trowel over low spots. Let this coat dry overnite. After that has dried, if needed, lightly trowel over a 3rd coat. Use a drywall sponge or plasterer mop and just dampen it. Run this over the final coat to smooth and "shine" the wall.
Or, after troweling on your first coat of 90 minute joint compound, you could try what guys call a D-mix. Buy a 5 gallon bucket of ready mixed joint compound. Remove the top 1/3 of the compound from the bucket and add 1 gal of PVA primer and also add 1 cup of Plaster of Paris to the remaining contents in the bucket. Stir this mix up and then let it slake for approx 5 minutes, then apply this mix to your walls using a paint roller with a 3/4 nap roll cover. After rolling a section of this on your wall, flatten out using a 12 or 14 inch drywall knife. I personally have never used this D-mix...but others on this website swear by it.
Good Luck.
Davo
Davo, how long do you have to work with the D-mix because of the plaster of paris added?
Could you post a picture of what is on the walls now?
It sounds like a thinned "roll coat". This was rolled on with a 1/2" roller. Most of the time it was thinned drywall compound. Rolled up and down it would look I guess like runny plaster.
Patching to match is not all that difficult. You need to knock off any 'tits' that would make your knife bounce. Apply tape (I use paper-could use fibreglass) to the joint of the patch. Bed it good, go both ways to even up the bumps etc.
Sand your patch, "wash off" the edge thats on the old work.
Now mix up your roll coat and test on a pc of scrap drywall. Once you get your consistancy-mix enough for the job, don't want to make more later-apply full strength to the new patch, rolling thinner as you go into the old work a foot or two.
After it dries you need to mimic 50 yrs of paint over the new roll coat. A rough glove rubbed over the whole shebang might help blend it in.
.
I've skimmmed whole walls and ceilings w/o a mesh base. Don't use bucket mud for the first coat. I use durabond 90, it has a high adhesive content. It dries super hard so don't plan on sanding that coat. Finish off with dry Lightwt 90 or regular Joint compound.
But a picture of what you got might change the whole process.
I second the "forget the mesh". I smoothed down a hallway that had a bad texture job. Based on advice from here, I ran successive skim coats. The first one was all horizontal strokes. The second was all vertical strokes. At this point, most of the holes are filled and you can do a last coat to finish it off.
Before skim coating the wall, I would try removing the texture from the plaster walls. Is it possible that it is a water soluble joint compound? Maybe use a wet sponge and carbide tip paint scraper?
Mesh is great if you have a lot of cracks....forget it if you don't need it.
Using a carbide scrapper it's easy to knock down the highpoints of the plaster. I use a 2" scraper all the time for this--non-carbide just won't hold an edge for long.
Then if you aren't used to applying a smoothing coat which is somewhat thicker so your knife doesn't bounce off the remaining highpoints, you are better off going up and down with one coat which will leave ridges where the knife bounces. You will want to try to smooth the ridges by going another direction but resist the temptation and let this coat dry completely. Then apply another coat 90 degrees to that to fill the ridges of the previous coat.
Go easy on the sanding as you'll bring out the highpoints of the plaster. Better to skim an area to smooth it out than try to sand--it's also easier to do.
Use a worklight at an angle to the wall to really show any inperfections. In areas that will have harsh natural light, especially glancing along at a sharp angle, things will have to be much smoother. Areas up high in shadows not so much. I use a lightweight 2' aluminum sanding block to check along the surface for how flat things are--normally 1/16" out is good except for harsh light areas.
As you get really close to being smooth apply a coat of slightly colored paint so you can see how things look. If you go to somewhere like Kelly Moore they sell any mis-tinted paints for $4 a gallon. For smooth walls I pick out 100% acrylic paint because it doesn't fuzz up during sanding.
applying the 1st coat
Hi Davo, what consistancy do I make the 90 minute skim coat? Just make it so the mud does not drop from my 12" blade?
I just bought the stuff to make the "D-mix", so will try that method. I have a 24" knockdown trowl, would that work better than the 12"?
Thanks
I, too, was curious about D-mix... so I tried it. I have to give it a thumbs down.
I'm not a plastering expert, and if D-mix takes practice I certainly didn't give it that chance. So take my comments for what they're worth, but my experience was negative to say the least. Perhaps my comments will shed light on this recurring topic.
First, the addition of PVA primer adds a whole new dimension to the term 'unholy mess'. Be aware that as careful as you may be, lots of this stuff will end up on the floor and you will step in it. Now you've got primer on the soles of your shoes and you will track it wherever you go. This, of course, is true of joint compound, or whatever medium you apply to the wall to skim... but nothing will be as hard to clean up or be as indelible as primer. This problem remains when you clean your bucket and tools. The PVA gets everywhere since unlike straight waterbase paint, you would be ill advised to simply wash things down the drain. So you will be out in the garden somewhere wondering what to do with a bucket of this stuff.
I thought the addtion of Plaster of Paris, or gauging plaster in my case, would help this material 'take a set'... Usually a finish plaster takes an initial set rather quickly, hardening to a point at which it can be screeded to, smoothed, or textured... D-Mix, however, remained the texture of the inside of a s'more, a gooey Marshallow-like consistency that would not set up for the longest time. I eventually scraped this mess off the wall and called it a day.
With all due respect to the advocates of D-Mix, my own conclusion is that it is a completely unnecessary and disadvantageous method of putting a skim coat up on a wall.
Since my escapade, I have used joint compound if I want a smooth texture. If I need to texture the skim coat, I add a little setting compound to the joint compound which gives it more body and helps it set up a bit much sooner.
Operator error? Possibly. But I will never go that stuff again.
gauging plaster instead of plaster of paris...
and a roller that don't hold the mix very well is a receipe for d- disaster.
genuine lamb skin 3/4" nap is the only way to go until and if we see a better d-mix applicator.
now you know first hand what NOT to do and use.
good luck next time.