If you've had someone “pressure wash” the house and the green came back the next summer, you already know the problem soft washing solves.
The short version
Soft washing is cleaning a surface with a cleaning solution instead of with force. The solution is applied at low pressure, about what a garden hose puts out, it sits on the surface long enough to kill what's growing there, and then everything is rinsed clean. The pressure is only there to carry the solution and rinse. It never does the scrubbing.
That's the opposite of pressure washing, where the force of the water does the work. Both have a place. On siding, paint, and anything else pressure would damage, soft washing is the right one.
Why it exists: the stuff on your house is alive
Most of what makes a house in Southwest Nova Scotia look dirty isn't dirt. The green haze on the north wall is algae. The black speckles under the eaves are mildew. The grey-green crust on the shingles and the old paint is lichen, and the cushions are moss.
All of it has roots, in the texture of vinyl, in the grain of wood, in the granules of a shingle. A pressure washer breaks the growth off at the surface and leaves the organism behind. That's why it grows back within a season, and why the second wash never looks as good as the first: the pressure has roughened the surface and given the next growth more to hold onto.
A soft wash kills it. Nothing left to grow back from. That's the whole difference, and it's why a properly soft-washed house here stays clean for two to four years while a pressure-washed one is green again by the next August.
What's in the solution
Three things: water, a professional surfactant, and sodium hypochlorite. Sodium hypochlorite is the active ingredient in household bleach, diluted to suit the surface. Siding gets a mild mix. The surfactant is a detergent that helps the solution cling to the surface long enough to work, then rinse away clean.
It's the industry-standard method, used on millions of homes, and it's the one asphalt shingle manufacturers recommend for removing algae and moss. We keep a plain-English breakdown, including how we protect plants and pets, on the what we spray on your house page. We'd rather explain it than have you wonder.
How a soft wash actually goes
- Pre-rinse everything green.
Plants, grass, and garden beds around the work area are soaked with fresh water. A saturated plant doesn't take up overspray.
- Apply the solution at low pressure.
From the ground and ladders, bottom to top so it doesn't streak, with a mix matched to the surface.
- Let it dwell.
Five to fifteen minutes, depending on the surface and the growth. This is when the killing happens. You can usually watch the green fade.
- Rinse, top to bottom.
Siding, trim, windows, and everything the wash touched, then a fresh-water rinse over the plants and walkways again.
- Walk it with you.
If something isn't right, we make it right.
What soft washing is right for
- Vinyl siding
- Painted wood and clapboard
- Cedar shingles and shakes
- Stucco and painted block
- Brick and stone
- Aluminum siding
- Garage doors, sheds and outbuildings
- Screened porches and gutters' outside faces
What it isn't right for
Concrete. Pavers. Anything flat, hard, and built to be walked on. Those surfaces take real pressure well, and they need it to lift grime out of the texture. We pre-treat the algae with a solution so it's killed, then clean the concrete with a surface cleaner for an even finish. That's pressure washing done properly, and it's a different job.
How to tell if a company actually soft washes
Ask what they're spraying on the house. A soft-wash outfit will tell you, straight, and explain the mix. Ask what pressure they run on siding; the answer should be “barely any.” Ask how long it lasts; the honest answer for this coast is years, not months. And look at the equipment: a dedicated soft-wash setup applies solution at low pressure from a separate system. A hardware-store pressure washer with a soap bottle on the wand isn't the same thing.
That last point matters here because almost nobody in the Tri-County soft washes. Most local washing is a pressure washer on a high setting, which is why the green comes back and the paint doesn't.
The long version, in one sentence
Kill it, don't trim it: that's soft washing, and it's why we do it on every house we touch. Ready to see it on yours? House soft washing has the details, or skip to the quote form with two photos.