Wall preparation for paint and paper
By Tom Phelan - ReminderNews
Featured Article - posted Tue., Jan. 17, 2012
You've decided to change the look of a room, including a fresh coat of paint on the walls. Even though you may be putting on a coat of the same color paint, there's a good chance that you are faced with a little more surface preparation than you thought. Walls have a way of racking up dings and dents over the years. And if those walls are papered, removing it will reveal a host of pockmarks, pits and gouges that will need more than a little attention. If you want a premium paint job, remember: preparation is everything.
The iterative process of applying wallboard compound and smoothing the dry surface is messy. You need to cover everything that's not being prepared. That includes you. Wear a hat or some other type of covering and work goggles to protect your eyes. Use a dust mask over your nose and mouth.
Use a hand sander to remove excess wallboard compound and the imperfections left behind by passes of the taping knife and compound. The correct technique requires light to moderate pressure, with a swirling action in different directions. Continuously sanding in the same direction can create more problems - ridges and gouges, as well as paper fuzz.
Hand sanding is not the best solution for some tight spaces, such as inside corners. Wet sanding is generally a better alternative. A drywall sponge is an inexpensive (less than $3) tool that has a course side and a smooth side. It also avoids the dust created by sanding. Use the course side to take away ridges and high spots, and the other side to feather edges and smooth the finished repair.
Joint compound isn't only for covering the taped seams between sheets of drywall. It is also used to fill depressions and smooth ridges. With your tool buttered with compound, make a smooth stroke across (perpendicular to) any gouge you find, then remove the excess by going in the same direction as the gouge. If you don't like the way it looks, repeat the two-step sweep. Let it dry completely.
When you tape and cover joints, the first pass will always create ridges on either side. It may look perfectly smooth to your eye when you first apply the compound, but as you run your hand across the width of the covered seam, you will detect the ridge. Once you prime it, it will become visible. Use the technique described above to feather out those ridges before applying the primer paint.
Those little razor utility tools can help clean up paper fuzz, nubs and ridges of joint compound, when used with a deft hand. They only cost about 99 cents, and use a standard single-edge blade. Hold the tool at a shallow angle to the wall - almost parallel - and gently knock off the fuzz and nubs and ridges of joint compound left by your tool. Be careful not to create a new gouge. Follow up with a quick sweep of a lightly damp drywall sponge, and you can move on to the next imperfection.
After working on the surface preparation for a day, let it all dry, and inspect it thoroughly in bright daylight or under a hand-held substitute. Stand at a shallow angle to the wall to highlight the remaining depressions, rough edges and frayed wallboard paper. Mark these locations lightly with a lead pencil, then make a final pass at curing the issues.
Have patience, and strive for perfection. Every little flaw on the surface will show up in the light of day after you have finished painting or papering the wall. Prime, sand and prime again. Once a wall has a coat of primer on it, you are likely to find there are still more imperfections. When you break out the compound and tools to fix those up, you will have to reapply primer. Unless you prime over bare compound, your final coat of paint will only make them stand out in those areas.
If you plan to paper the wall you just rehabilitated, be sure to cover it with primer, followed by an application of a wall sizing mixture. This solution prepares the wall to receive and bond with your wallpaper. If you ever have to remove that wallpaper, you will rue the day you took the short cut, skipping the primer and sizing.
There is no compensating for a wall that is not flat and straight. You can make neat seams, and do a professional job of taping and covering them, but you can't cure wavy wallboard and corners that are not true 90-degree angles. You can, however, mend and prepare the surface to eliminate and cover the vast majority of its imperfections.