House Washing

What those green and black streaks actually are

Siding in New Jersey does not get dirty so much as it gets colonized. The green film is algae, the gray-black speckling is mildew and mold, and both of them live on the moisture that sits on a shaded wall long after the rest of the house has dried. That is why the north side of a home always looks worse than the south side, and why the wall behind the arborvitae is the first to turn.

Because it is growth rather than grime, blasting it off is only half a job. The colony leaves roots in the texture of the siding, and within a season it is back. A soft wash treats the surface with a cleaning solution first, kills the organism outright, and then rinses everything away at low pressure.

How we wash a house

1. Walk the property first

We check the siding type, look for loose panels, chalking paint, open weep holes and any window seals that have already failed, and point out anything we find before we start rather than after.

2. Protect the landscaping

Beds, shrubs and lawn edges are soaked with clean water before anything else happens. Wet foliage does not absorb solution, and a rinse afterwards carries off whatever settled.

3. Apply and dwell

The solution goes on from the bottom up so it cannot streak, and it sits long enough to do its job. This is the step most rushed jobs skip.

4. Rinse from the top down

A low-pressure rinse takes the dead growth off with it, including the film on your windows and frames. We finish by flushing downspouts and washing down walkways and driveways where runoff has traveled.

Surfaces we handle differently

• Vinyl and aluminum — the most common siding here, and the most commonly damaged by high pressure. Low pressure only.
• Stucco and EIFS — porous and easily eroded. Gentler solution, even gentler rinse, extra care around any hairline cracking.
• Brick and stone — tolerates more, but the mortar joints do not. We keep pressure off the pointing.
• Cedar shake and painted wood — cleaned at the lowest strength that will work, because the goal is to save the finish, not to strip it.

When to book it

Spring and early fall are ideal, but any month above freezing works. If you are listing the house, book two weeks out — clean siding photographs better than anything else you can do for the money, and it is the first thing a buyer sees from the curb.