Before the scrubdown, protect nearby plants by misting their leaves and saturating the surrounding soil with water, pulling them away from the house, and shrouding them in fabric drop cloths. (Plants will cook under plastic.) Lay more drop cloths along the base of the walls to collect any falling paint debris. Walls should be wet down before getting scrubbed, then washed with a gallon of water mixed with 1 cup chlorine bleach and 1 cup of either a concentrated, phosphate-free cleaner, such as a trisodium phosphate (TSP) substitute, or Jomax House Cleaner. Working in sections, from the bottom to the top, will avoid streaks. Be sure to rinse walls well before the solution dries. Wood siding and trim should be ready to paint after a day or two of dry weather.
Repaint — exteriors especially — before visible signs of wear appear, Bancroft says. Don’t wait until you see peeling or flaking paint. “If I have to spend 40 hours preparing the surface before we can paint, that time is going to result in a lot of extra costs. But if I can spend 10 hours preparing the surfaces to be painted, you’re going to save money,” Freeman says.