By August the north side of most houses in Putnam County and the Hudson Valley has a green tint, the roof has dark streaks, and the deck is slick after a rain. That is algae, mold and mildew, and it does not go dormant over winter. It holds moisture against siding, shingles and wood while everything freezes and thaws, which is how small cosmetic problems become rot and failed finishes by spring. The fix is a soft wash in late summer or early fall, while the weather is still warm enough for the cleaning solution to work and the surfaces to dry.
Soft washing versus pressure washing
A pressure washer cleans by force. At 2,500 to 3,000 PSI it will strip algae, but it also drives water behind vinyl siding, lifts shingle granules, raises the grain on cedar and etches soft wood. We see the damage all the time: fuzzy deck boards, wavy siding and roofs that shed grit for a year afterward.
Soft washing uses roughly garden-hose pressure and a biodegradable cleaning solution that kills the growth at the root. The solution does the work, then it is rinsed off. Siding, roofs, painted surfaces and composite decks come clean without being blasted, and because the organisms are dead rather than just knocked off, the surface stays clean two to three times longer.
What should be cleaned before the cold
Roofs first. The black streaks on asphalt shingles are a type of algae that feeds on the limestone filler in the shingle. Left alone it shortens the life of the roof, and in winter the moss and lichen that grow with it hold ice against the shingles. A fall soft wash removes it and the roof dries clean before the first snow.
Siding next. Vinyl, fiber cement, aluminum and painted wood all grow mildew in the shade. Washing it off before winter means you are not sealing a season of moisture behind the siding, and the house looks right through the holidays. Soffits, fascia and gutters get cleaned at the same time.
Decks, patios and walkways last. A clean deck is a safe deck. Algae on composite or wood decking, concrete steps and bluestone walks is the main reason people slip in November. If a wood deck is due for stain or sealer, the wash has to happen first anyway, and the warm weeks of September are the window to get both done.
Timing and weather
Soft washing works best above 50 degrees, with a dry day or two afterward. In our area that means late August through October for the exterior of the house, and ideally before the leaves come down so the roof and gutters are not immediately covered again. We can wash into November if the temperatures cooperate, but earlier is easier.
What to expect from us
We cover plants and pre-wet the landscaping, close windows and vents, apply the solution from the ground or a ladder, let it work, and rinse. A typical house takes a few hours. Nothing is scrubbed, nothing is blasted, and the results are visible before we leave. For roofs, the streaks fade over the following week or two as rain washes away the dead growth.
Soft Wash by Putnam Handyman serves homeowners in Putnam, Westchester, Dutchess, Fairfield and Litchfield counties. See our soft wash page or request a free estimate, and get it on the calendar before the leaves fall.