How to Get Rid of Mold Before Exterior Painting

Before painting the exterior of your home, the surfaces need to be dry and clean. This means removing mold, dirt and loose paint. Mold can be tricky to spot. It can be difficult to distinguish from dirt, and it's not always the classic black discoloration. It can be gray, white or green. Identifying and getting rid of small areas of mold can be done by hand, but you may want to consider a power washer to thoroughly clean your entire house before exterior painting.

Bleach
Trisodium phosphate
Siding detergent
Hose
Power washer
Five gallon bucket
Scrub brush
Extension pole
Ladders
Gloves and protective gear

Instructions

- 1
  Identify the moldy areas. Use ladders or binoculars to get a close-up look at high spots in the eaves and soffits. If you're not sure whether black discoloration is mold or dirt, mix 1 part household bleach with 3 parts water; spray it on the discoloration. Mold will very quickly turn light brown and disappear, while dirt will remain unaffected.
- 2
  Mix together 1 part household bleach and 3 parts water into a spray bottle or garden sprayer. Apply the solution to the mold. Wait 10 to 15 minutes; rinse well. Use a scrub brush for heavy mold or mossy growths.
- 3
  Use a power washer for extensive mold. Most power washers have a detergent function, allowing you to soak the surface with detergent, then switch to high pressure mode for rinsing. Don't use bleach in power washers; it ruins the seals. Instead, use a commercial siding cleaner containing mildewcide for the mold removal.
- 4
  Allow the house to dry. Inspect it again before starting to paint. Priming or painting over mold will cause adhesion problems and paint peeling.

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