Extensive preparation and painstaking application are the yin and yang of a good interior paint job. They're equally important. Skimping on one will ruin the other. How well the surface is prepared will determine how well the paint goes on; how well the paint goes on will determine whether the finished surface looks professional or amateurish.
Of course you can hire professionals to do the painting, with a result that is swift and (very likely) neat.
But in fact, painting is one of the easier skills to learn, and it's very rewarding when you see the transformation you've wrought in a room. The tools are simple and inexpensive: brushes, rollers, roller covers, paint pans, masking tape, dropcloths or old newspapers, rags or paper towels, mineral spirits for clean-up if you're using oil-based paint.
Should you use oil-based paint? A few years ago the answer would have been an unequivocal yes, if you're painting trim, a bathroom or a kitchen. But today's acrylic paints are as impermeable and scrubbable as oil, and far easier to clean up. Oil is still a good choice for some uses. You should always use oil-based primer on fresh plaster. The alkali in the plaster will make latex paint peel right off. Oil-based primer is good on bare wood because it seems to seal the porous surface better, and oil-based finish paint is preferred for wood trim.
Oil-based paint "levels out" better than latex on wood trim, according to Larry Horton, store manager at Budeke's Paints in Fells Point, Md. That means a smoother, more elegant finish. Latex may dry so fast the brush marks remain or the ridges from roller strokes' overlap can show. Water-based paints have come a long way, Horton says, but they still don't have the quality look of oil finishes.
On the other hand, you should never use oil-based primer or paint on bare dry wall. It will raise the nap on the paper surface and give you a terrible, rough finish.
Whichever paint you use, don't hesitate to thin it a little if it seems difficult to apply. Manufacturers don't like to think of you dumping water or mineral spirits into their paint (regardless of what it says on the can), and there are products on the market that will keep the edges wet longer and help prevent ridges and lines. Floetrol, from the Flood Co., is for water-based paint. (Horton said it's especially useful in painting a ceiling.) Flood's Penetrol, for oil-based paint, keeps the edge wet longer and and makes the paint flow better.
Whatever you put in the paint, add it in tiny increments. If you thin it too much, you will get drips and runs.
Finally, don't skimp on equipment. Cheap brushes shed, and the bristles that stay in may be too stiff to give you a smooth line. If you're using oil-based paint in a gloss, eggshell or satin finish, buy mohair roller covers. Use metal paint pans; the plastic ones aren't sturdy enough for many trips up and down a ladder.
If you haven't done a lot of painting, it may be hard to get the sequence of tasks right. The following are the steps, in order, involved in preparing surfaces and painting trim.
1Remove or cover up furnishings, including rugs and curtains or shades. If the floor is carpeted, use a dropcloth. If you're painting trim that adjoins the carpet, tape off the edge of the carpet with wide masking tape and overlap the edge of the drop cloth. On bare floors, tape off the edge and overlap with drop cloth or papers.
2Take everything off the walls, including switch plate covers and telephone box covers.
3Patch holes and cracks with joint compound or wood filler. Sand all rough areas, including patches, when they're dry. If underlying paint has a gloss finish, it should be sanded so it will accept the new paint better. All trim should be sanded before painting.
4Clean and dust all surfaces. Dust is a deadly enemy; if you want a smooth, professional-looking finish you have to keep dust off the surface, off the brush and out of the paint. If there's a problem with mildew or stains, clean the surface as well as possible and coat with a layer of mildewcide-stain killer. (Be sure to use proper ventilation, because most of these products are alcohol-based.)
5Paint the trim first. If it's bare wood, the initial coat should be a good-quality oil-base primer. Top with two coats of finish paints. If the trim is already painted and you're not sure what kind of paint it is, use an oil-based primer first. Then you can top that with either oil or water-based paint. Painting a lot of trim can get tedious. You can speed up the process by using a small roller on flat areas; go over it immediately with a brush so the texture will match the brush-painted areas. Let the trim dry completely before moving on.
6Windows are easiest to paint when they're out and lying flat. If you must paint them in place, try to apply paint sparingly along the edges so you don't paint them shut. You can tape off the glass with masking tape, or just try not to get too much on the glass and scrape it later. Inexpensive window scraping tools are available that make the task extremely easy.