I’m looking for tips on patching painted drywall. Because the patches are mostly butt joints, the mud will need to be feathered out a long way to hide the seams. The feathered mud will be thin and I want it to stick to the paint so it doesn’t flake off in a year or two.
What is the best way to get the feathered mud to stick to paint? Scuff sand the paint, primer over the paint, etc.? Is there any way to keep the paint from gumming up the sandpaper at the edge of the feather?
I’m also interested in any tips to minimize the dust. Thanks.
Billy
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Patching painted drywall is a common by-product of my work. In my case, it is almost always handled by another trade. In watching them - they usually need to match a texture as well as patch - I've never seen any special preparation work done. It seems the mud has absolutely no trouble sticking to the paint just as it is.
Otherwise, for a glossy paint, a wipe down with TSP is probably a good idea.
Thanks, Reno -- I appreciate it.
Billy
All I can add to reno's is MAYBE scratch the surface. High gloss oil paint on rare occasion might not allow good bonding.
Usually though I would use a good bonding product such as non topping readymixed or durabond for the first coats. Be wary of durabond, dries fast and hard. Not a good "only" patch-needs to be covered with something less coarse and easier to sand. Doesn't really skim out thin enough either.
If you were ever real concerned, a first coat of plaster weld will give real good adherence. I only use it when dealing with old plaster that might contain "something" that sometimes causes peeling of the skim coat.
A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
First of all, DON'T use fiberglass mesh tape. It's too thick for butt joints. If it's a small patch, say less than 20"X20", you might want to consider a wet-and-stick crack repair tape. The one I use is thinner than regular joint tape so less feathering is needed. If the repair is completely contained within a sheet of drywall, you can use a self-adhesive joint tape. It's not as strong as regular joint tape, but strength isn't really needed in this case.
I have never had a problem with compound (setting, ready-mixed, 1st coat or topping) adhering to a painted surface. If you really want to be sure, it can't hurt to sand it or use a primer. Use a 100% acrylic primer, they adhere better.
The "trick" to minimizing dust is to minimize sanding. I patch most small holes with 2 coats, feathered out 6 - 8 inches and with minimal sanding. If the patch is not a perfect fit, I'll do a first coat to fill any voids before I tape the joints. So that would make a total of 3 coats. It took a lot of mistakes to get to this point. If you haven't done much spackling, plan on several very thin coats (keep steady pressure on the taping knife) feathering out further and further with each successive coat. 4 or more coats would not be unreasonable for your first few patches. Each coat should be thin enough that no sanding at all is required between coats, but you may need to knock of the ridges (ok, you can use sandpaper on the ridges if you must).
There is a "dust control" joint compound that clumps as it's sanded so it falls more directly to the floor without getting airborne. It really works and you might want to give it a try. All of your topping coats should use the same joint compound. Each one sands a little different.
I wouldn't expect the paint to clog the sandpaper. If it does, you're sanding way too vigorously.
Hey, Don-
have you tried Zano's tool yet?
JLC had a review of it a month or two back. I'm thinking about getting one. It would come in handy at times.
Oh yeah! Thanks for reminding me that I still have the "Butt Taper". I still think it's a good idea, but it's funny how since I bought it, I haven't needed it. Before that, it seems like I could have used it every other week.
And my offer still stands... if you ever want to use it (try before you buy), all you have to do is pick it up and return it.
Thanks for the offer. I might take you up on it, if I can plan far enough ahead to be able to pick it up before I need it. LOL
I use LaFarge brand joint compound. I am very often asked to do a patch over painted surfaces. I never had a problem with the mud sticking to painted surfaces, always works like a charm. This also is true back when I was dumber and was using Sheetrock brand mud which I'll never go back to using. Do your patch, prime and paint, you'll be fine.
My method for making patches uses NO tape. (Butterfly Patch)
1. Cut your patch 2" wider & taller than the hole.
2. Then cut thru the drywall paper and remove a 1" border all around the perimeter of the hole. Just the paper.
3. From the backside of your patch. Cut a 1" perimeter in the rock. Break and remove. Keeping the 1" of paper intact on the front of the patch.
4. On small patches I don't use any backing. Just butter it up good in the joints. The flap from the patch, acts like the tape in a normal repair.
Fairly strong and low profile, you can make it disappear with a 2nd coat of mud.
I'm just trying to understand step 4. Do you put any mud between the flaps or do you put the patch on dry and mud over the patch ? And what exactly do you mean when you say that you don't put any backing on small patches ?
I think this whole forum would have a good laugh over my first patch.
Yes, treat the flaps as you would tape. Apply mud, then squeeze out with your knife.
Backing- Plywood or lumber screwed to existing drywall and patch, so patch doesn't fall thru.
On smaller patches- 12" X 12" or smaller, omit the backing and you can recess the patch slightly. Less area to feather out.
Less is more....never try to leave anything but a thin layer of mud.
Here's a good video of Myron Ferguson taping seams.
http://hwtv.jlconline.com/default.asp?bcpid=1184514373&bclid=1184468643&bctid=1232412926
1. give the wall a good sand.
2. depending on the severity of the repair, you can use Durabond90 for your 1st coat on joints or large patches. Be sure to put it on thins because you don't want to sand.
3. I like CGC Ultra Light drywall compound for my finish coat. I usually add a little water to thin out the mud and mix it up really well. Let it sit a few minutes before using. This will to keep the water separatnig from the mud. Scoop it out of your pail and onto your hock and work it over with your knife a bit to get the air bubbles out. (important for the final finish) - Put the mud on thin. If done properly, you should only need to sand once at the end.
4. Use a "primer/sealer" to prime with. This will help to cover any imperfections.
5. Use a good quality wall paint. I prefer SICO. Don't know what is available in your area.
6. Use a good quality medium texture roller (medium semi smooth), preferably lint free. This will help to blend.
7. You may need a 3" brush to feather the outside edges of the repair, ...unless you plan on painting the entire wall. You may end up having to as it can sometimes be difficult to make a decent match after doing a repair like this.
Dave