Similar to exterior mold, mold is more likely to emerge in warm and humid areas. That being said, rooms like bathrooms and basements are more prone to mold. To preemptively prevent mold, use paints that are mold resistant. Should you find mold on a wall in your home, you can clean it with a simple solution of one part bleach to four parts water. If the area is large, you may want to leave the cleaning to a professional.
Prime. Dark colors, stains (once sealed), and previously unpainted surfaces (drywall, spackle, etc.) will need a primer coat, usually white. NOTE: most paint stores & home improvement centers will now tint primer (at no charge) to match fairly close to the color of the finished coat, that way two coats of primer need not be applied. Although not all surfaces need a prime coat, skip this step at your peril! Dark colors will likely show through the first -- or even the first couple-- topcoats of paint. Sealants and unpainted surfaces like spackle patches will absorb or repel moisture in a topcoat at a different level than the areas surrounding them. Applying a good primer coat will help even out these differences. Primer equalizes a wall to a uniform surface. It's like erasing a canvas before drawing a new picture. Although some will argue the point, you generally don't need to spend a great deal on primer or buy special primer. A cheap, 5 gallon (18.9 L) bucket of plain, flat white paint will usually do the trick and cover a large area. Give your primer at least 24 hours to dry (follow its instructions) before applying a topcoat.
Dirt and grime are bound to develop on exterior house paint after some time. Luckily, you can easily clean your home with a pressure washer. It’s recommended that you pressure wash your home about five or six years after the initial paint job. For areas like porches and overhangs, you should clean them more often. Taking a garden hose to these areas once a year should do the trick.
From dull to shiny finishes, paint comes in several different lusters. A paint’s luster depends on its mixture of pigment, resin, and additional ingredients. If you’re struggling to decide what finish you want, note that glossier finishes tend to be more durable and washable. Flat paint, on the other hand, is better at hiding surface imperfections. Pearl and eggshell lusters fall somewhere in the middle, as they are more washable than flat paint and partially hide irregularities.