- The green film is usually algae or mildew, fed by shade and humidity.
- Start gentle: a soft brush, a garden hose and a cleaner made for siding.
- Many homeowners hire a pro for a soft wash, especially on tall walls.
Walk around almost any house in Hampton Roads and you’ll find a green tint on the side that gets the least sun. Long humid summers, shade from trees and dew that lingers in the morning give it everything it needs.
What it isAlgae, mildew and pollen
That green or gray film is usually algae or mildew, often mixed with pine pollen. It grows fastest on north-facing walls, behind shrubs and under trees.
CleaningStart gentle
A soft brush on a long handle, a garden hose and a cleaner made for your type of siding take care of most of it. Work from the bottom up and rinse from the top down, and cover nearby plants first.
Gentle and regular beats strong and once a decade.
PressureGo easy with a pressure washer
High pressure can force water behind vinyl siding and strip paint from wood. If you use one, keep the pressure low and spray down the wall, never up under the laps. For tall walls and second stories, many homeowners hire a pro for a soft wash.
Keep it awayHelp the wall dry out
Trim shrubs back from the house, keep sprinklers from hitting the siding and keep gutters flowing. A wall that dries faster grows less.
