2. Clean first: The most important step as you prep is to rid your home's surfaces of salt spray and moisture that can prevent paint from adhering well, Spillane says. For a quick DIY cleanser, try mixing 3 quarts warm water with 1 quart household bleach, and adding 1 cup Trisodium Phosphate (TSP), a heavy-duty cleansing powder available at home improvement stores.
3. Smooth it out: If you're applying paint to an exterior for the first time—or if the existing paint is badly weathered—it's a good idea to apply a primer soon after the clean surface is dry, Spillane says. Primers smooth out the grain of natural wood and seal any imperfections in painted wood. If the existing paint is in good shape, skip the primer and apply two coats of paint for a sleek job.