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What Is Soft Wash Roof Cleaning and How It Works

Soft-wash roof cleaning is a low-pressure cleaning method that uses a mixture of water, detergents, and chemicals to remove dirt, stains, mould, mildew, and other contaminants from roof surfaces. Unlike pressure washing, which uses high-pressure water jets, soft wash roof cleaning relies on chemical solutions and lower water pressure to lift contaminants and restore the roof.

How Soft Wash Roof Cleaning Works

The soft wash roof cleaning process involves these key steps:

  • Inspect and Prep the Roof: The roof is first inspected to identify any damaged or loose areas that need repair prior to cleaning. The surrounding areas are then prepped by covering any landscaping, windows, doors, etc. to prevent overspray.
  • Apply Cleaning Solution: A soft wash cleaning solution made up of detergents, surfactants, bleach, and water is then applied over the entire roof surface using a garden sprayer or agricultural sprayer. The solution lifts and dissolves dirt, stains, mould, and other contaminants.
  • Let Dwell and Rinse: The cleaning solution is allowed to dwell on the roof for 10–20 minutes to allow the chemicals time to work. A low-pressure rinse (less than 300 PSI) is then used to rinse away dissolved contaminants. Any remaining solution is left to dwell further and rinse off naturally with future rains.

The soft wash cleaning solutions used are specifically designed to eliminate roof contaminants like mould, mildew, algae, lichens, and atmospheric dirt and stains. The solutions are also safe for use on all roofing materials when used correctly, including asphalt shingles, wood shakes, tile, metal, and composite roofs.

Benefits of Soft-Wash Roof Cleaning

There are several key benefits that make soft wash roof cleaning an effective and preferred method:

  • Less Damage: Soft washing is gentler on roof materials compared to pressure washing methods that can damage shingles and surface coatings. The low-pressure rinse also reduces splashback and overspray.
  • Deeper Clean: The cleaning solutions dissolve and lift contaminants more effectively compared to just using water. Solutions get deeper into the roof materials for a more thorough clean.
  • Eco-Friendly: Soft wash solutions are specifically designed to be biodegradable and environmentally friendly. They target contaminants without harming surrounding areas.
  • Cost-effective: Soft washing uses less water and requires less equipment compared to pressure washing, making it a very cost-effective cleaning method.
  • Longer Lasting: By removing all biological contaminants and stains down to the roots, soft washing provides longer-lasting results compared to just surface cleaning methods.

When To Get Soft Wash Roof Cleaning

Homeowners should consider getting a soft-wash roof cleaning done when:

  • Visible mould, mildew, algae growth or black streaks appear on the roof
  • The roof appears notably dirty, stained, or dull-looking
  • To maintain roof warranty requirements
  • Every 2-3 years as preventative maintenance

Getting roofs regularly soft-washed every few years keeps them looking new, prevents long-term damage, and extends the roof’s lifespan significantly.

Differences from Pressure Washing

While both soft washing and pressure washing use water and detergents to clean, there are a few key differences:

Water Pressure

  • Soft washing uses less than 300 PSI
  • Pressure washing starts at over 1000 PSI


  • Soft washing is gentle and lifts contaminants through chemicals
  • Pressure washing forcefully scrapes and strips contaminants


  • Soft washing relies on chemical solutions.
  • Pressure washing relies on mechanical water force


  • Soft washing causes less splash back and overspray
  • Pressure washing can damage materials and surrounding areas with uncontrolled water

In most cases, soft washing is the safer, more effective cleaning method recommended for roof surfaces. Exceptions would be concrete tile roofs that can handle higher pressure levels.

Soft Wash Roof Cleaning Equipment

The basic equipment needed for soft-wash roof cleaning includes:

  • Low-pressure washer: Capable of less than 300 PSI with variable nozzle tips
  • Garden sprayer or agricultural sprayer: For applying cleaning solutions
  • Soft wash cleaning solutions: Specially designed detergent mixes and chemicals
  • Hoses, ladders, and accessories: For access and roof prep

Commercial soft wash systems also utilise specialised low-pressure pumps and chemical injection systems to increase efficiency on large jobs. Safety equipment like harnesses and roof access platforms may also be used to safely access and manoeuvre on roofs.

Hiring a Professional Soft Wash Company

While the soft wash roof cleaning process may sound straightforward, it's critical that it is done correctly and safely to avoid roof damage or environmental contamination. Hiring a professional soft-wash roof cleaning company is highly recommended.

Reputable soft wash companies have the right equipment, knowledge of roof materials, and experience necessary to thoroughly clean roofs while protecting their integrity. They also have specialised cleaning solutions tailored to specific roof types and can properly prep and protect surrounding areas. Their expertise allows them to safely navigate roofs to fully access and clean all surfaces.

Trying to self-wash a roof without professional experience risks missing contaminated areas that can continue damaging the roof. It also poses safety hazards for both the cleaner and the roof if attempted without proper precautions, training, and equipment.


Regular soft-wash roof cleaning provides a safe, effective, and eco-friendly way to thoroughly clean and maintain roof surfaces. By lifting contaminants and restoring roofs down to the roots using specialised low-pressure equipment and cleaning solutions, soft washing keeps roofs looking their best while extending their lifespan. Hiring a professional soft wash company ensures the job is done properly to realise all the benefits this superior cleaning method offers.

Harry Virk

Harry Virk is the director of CleaningPro Auckland. He has years of experience in the cleaning industry and his company is expert at providing exceptional cleaning services in Auckland. He has a passion for helping people and making sure that their homes are clean, tidy, and ready for visitors.

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