Soft Washing: The Safer Way to Clean Your Home's Exterior
Not every surface on your home can handle the force of a pressure washer. Roof shingles, painted wood, stucco, EIFS, and older brick can all be damaged — or even destroyed — by high-pressure water. Soft washing solves this problem by using low pressure combined with professional-grade cleaning solutions to kill and remove organic growth at the source, leaving surfaces cleaner for longer without any risk of damage.
What Is Soft Washing?
Soft washing uses water pressure under 500 PSI — roughly equivalent to a garden hose — combined with biodegradable cleaning solutions to clean exterior surfaces. The chemistry does the work, not the force. Solutions typically contain sodium hypochlorite (bleach) at controlled concentrations, surfactants to help the solution cling to vertical surfaces, and neutralizers to protect plants and landscaping.
The result is a deep clean that doesn't just remove visible staining — it kills the algae, mold, mildew, and bacteria at the root, preventing regrowth for 1–3 years depending on the surface and environment.
Soft Washing vs. Pressure Washing: Which Does Your Home Need?
The right method depends entirely on the surface. Pressure washing is best for hard, non-porous surfaces that can withstand force: concrete driveways, brick patios, stone walkways, and metal fences. Soft washing is the correct choice for anything that could be damaged by high pressure.
Surfaces that should always be soft washed include asphalt shingle roofs, wood siding and trim, painted surfaces, stucco and EIFS, cedar shake siding, and screen enclosures. Using a pressure washer on these surfaces risks stripping granules from shingles (voiding your roof warranty), gouging wood, cracking stucco, or forcing water into wall cavities.
A professional exterior cleaning company will assess your home and recommend the right method — or a combination of both — for each surface. Many jobs use pressure washing on the driveway and walkways while soft washing the house itself.
Why Pittsburgh Homes Develop Algae and Mold So Quickly
Pittsburgh's geography makes it a prime environment for organic growth on home exteriors. The city sits in a river valley with high ambient humidity, and many neighborhoods feature mature tree canopy that keeps north and west-facing surfaces shaded and damp for much of the year.
Gloeocapsa magma — the black algae responsible for the dark streaks you see on roofs and siding — thrives in exactly these conditions. It feeds on the limestone filler in asphalt shingles and spreads via airborne spores. Left untreated, it retains moisture against your roof, accelerating shingle deterioration and potentially shortening your roof's lifespan by years.
Soft washing with the correct sodium hypochlorite solution kills Gloeocapsa magma and other organic growth on contact. The results are immediate and long-lasting — most treated surfaces stay clean for 2–3 years before retreatment is needed.
Is Soft Washing Safe for My Landscaping?
When performed by a trained professional, yes. The key is proper dilution, pre-wetting plants before application, and thorough rinsing of all landscaping after the job. Professional soft washing solutions are formulated to break down quickly and are applied at concentrations that are effective on organic growth but safe for established plants when handled correctly.
A reputable company will take precautions to protect your flower beds, shrubs, and lawn — covering delicate plants if necessary and rinsing the surrounding area thoroughly after cleaning.
How Long Does Soft Washing Last?
Soft washing lasts significantly longer than pressure washing alone because it kills the organic growth rather than just removing the visible staining. On roofs, results typically last 2–4 years. On siding, 1–3 years is common depending on sun exposure, tree cover, and local humidity.
Pressure washing, by contrast, removes surface-level dirt but leaves behind the microscopic roots of algae and mold. Regrowth can appear within months. Soft washing's chemical treatment eliminates regrowth at the source.