D.I.Y. wall repair - any advice?

Is is plaster or dry wall?


I'd do with #1. Sand the paint down if you can and then spackle with a large enough blade. Sand, spackle, sand, spackle over and over until it's smooth. If it's not smooth do it again and again. Often you have do a area 4-6 inches larger than the bumps.

They should be the ones to fix it...

If you want to do it yourself -- follow mydo's advice...

Like Mydo said, it makes a difference if it's plaster or drywall, but in general:

Your main areas of concern are: adherence and slumping.

Adherence you address by thoroughly sanding the problem area with medium grit sandpaper. If there is any loose material, knock it out now. You need to get the entire area at or slightly below surface level. Then, clean clean clean. Needs to be dust and paint free.

A random orbit sander with a medium coarse grit will speed things along, but you will make a lot of dust. Most random orbit sanders have a dust port, if you can get one hooked up to a shop-vac of some sort it will save a lot of clean-up time and possibly hazardous dust. Wear a dust mask, and If it's an old wall with unknown paint and composition be very careful.

Slumping (the stuff you apply moving downward while it dries) is a matter of choosing an appropriate patching material, out of the many options, and applying in thin coats.

For what you are describing I would suggest wall-board joint compound if it's drywall; an amended plaster liker Polyfilla if plaster.

Using a wide joint knife (like a "putty knife" but wider and more flexible, about 8") apply a thin coat of the repair material to the affected area, feathering it out beyond the edges of the patch, and let dry. Sand lightly, clean, and repeat, until you've built up enough material to bring things slightly above surface level, then one last sanding to make it flush. Let dry for at least a day before repainting.

This works for shallow depressions up to about a foot in diameter. If your whole wall is one big wave, you may have to live with it or start wholesale replacement of things.

just drink all that Guinness, im sure it will look pretty even after that.

I think I understand better now. Basically you have to start with a clean surface. Remove anything peeling up. Use a utility knife to help cut a border around stuff peeling up. That way you can start with a clean surface. Your spackle knife needs to be wider than the area you're trying to patch.

If you're good (or you have help) you can follow your sanding hand with a vacuum hose in the other to keep dust down. Or if it's a small job you can tape a paper bag under the patch and most of the dust falls in it.

Spackle is forgiving in that if it looks bad just sand it smooth and put on another smear. Use your hand to check how smooth and even it is. If it looks good before you paint it will look great after you paint.

The previous owner of my house was a crappy patcher. He used wet sanding too much and basically makes the patch wavy rather than smooth. I have years of patches to fix in my house.

You've just described dry wall( or wall board as it's called elsewhere). Read addabox's technique, that 'll work well. It's not to hard but you'll need to go and buy the proper tools in order to achieve a result that you'll be happy with. Just make sure you know what your wall is made of. With dry wall you'll need joint compound to smooth your wall. With a true plaster wall you'll need may need different material, I'm not sure as I've never fooled with a plaster wall.

This really does sound like drywall and not plaster.

I'll add my two cents. I have experience doing a few wall board jobs, replacing missing or broken boards. They turned out well, and I just finished patching a wall a week ago.

Yes, as noted earlier, you need premixed joint compound (mud) and LOTS of it. Unless you are a pro, stay away from the stuff you must mix. Start with a gallon and see whether this is enough. Do not use spackle, which is for small holes and things like that.

You must sand down the high spots, and then fill in the low spots. Expect to do at least three coats of mud, or more. Allow each coat to dry completely and then use a sanding screen to take down any high spots. When working with mud, sandpaper clogs up too fast. You attach the screen to a flat board like you would sandpaper, but you can bang it on a hard surface to knock off the excess dried mud. I find that stapling it to the board works well. Bend the screen over the edge and staple on the back side, with a staple gun.

I have not had trouble with mud sticking to paint. I never sanded low spots down to the paper surface of the wallboard, ever. Spread on a thick coat with a 4 to 6 inch putty knife. Then use something like a 12 inch knife to smooth it out. The trick is to remove a lot of mud, which you can then spread on other low spots. The more you take off here, the less you need to sand off with the screen. If it isn't perfect, and still has some low spots, let it go, and get it on the next coat. Don't spend time trying to make the first coats perfect.

On areas where the low spot is deep, the mud will shrink and you will need more coats than on thinner low spots. When you finish, use a coat of primer on the patched part of the wall. I like Acrylic water base primer. Once it is primed you may notice a few more blemishes, which you can fix with a little more mud. Once all the mud has been primed, and you are satisfied, you can paint with a finish coat.

Have fun. :

Keep in mind, he's not literally talking about mud...

It occurred to me you might have gloss or semigloss paint, which can be a problem. I have always worked with a very flat, or matt, finish paint. If you do have a glossy or even slightly glossy finish, you have two option.

1. Sand paper it down to a flat, non-shinny surface.

2. Give it a coat of white shellac, which sticks to just about anything. It may go under the name stain guard, but be sure it is alcohol based shellac, not oil based.

Fixing dry wall is not that hard. You will get better each time you do it. You might as well get several putty knifes 2", 6" and 12". If you clean up afterwards they will last many years. Once you start having kids, especially boys, you will find that fixing walls yourself is cheaper than going out and having someone do it for you. Unless you have a friend that only requires a six pack to do the job. As for using polyfill. I find it good for using in bathrooms or if the tape is coming off a corner and you don't want to redo the whole corner.

I think that's good advice! My tools get used every so often. Justin, the 2 inch knife is good for small holes or cracks. For these tiny jobs I use a light, fluffy spackle, which dries fast and can be paints almost immediately. Joint compound, however, can be used on any size job, big or small. If you keep the lid on tight, it keeps a long time.




Have you priced the tubes? How many would it to make a gallon? If your wall is very large you may need more than one gallon. Premixed joint compound is usually cheap by the bucket. Most important, however, it dries with a hard surface, and is easy to scrape or sand off any excess. Most things in tubes stay a little flexible and don't sand easily.

Regarding tools, drywall and plaster use different tools usually. I use a 4 or 6 inch putty knife to get the mud out of the bucket and spread it generously on the area that needs it. The 12 inch drywall knife is used to take off excess mud and move it to the next location. If you use sufficient force with the large knife, the mud will be very flat and you will have little or none to sand down. If there are indentations in the smooth mud, it's best to let it dry that way and fill on the next coat. I also have an 8 inch drywall knife too, but don't use it as much.

BTW, if you find any nails coming out, their heads breaking through the surface of paint, pull them out. Do not hammer them back in. They will only come out again. Replace missing nails with wallboard screws. Usually 1-1/4 inch are good enough, but 1-5/8 is more common. Tighten the screws down so the head sinks below the surface of the wall, then cover with mud.

Sorry all the units have been in the English/US system. I don't know the equivalent standard sizes in metric.