What is Soft Wash Roofing Cleaning? (How it Works, Chemicals, and Equipment Guide)

In this article, we will discuss the process of soft wash roofing cleaning, its benefits and drawbacks, as well as the equipment and chemicals used. By the end of this guide, you will have a better understanding of soft wash roofing cleaning and how it can benefit your home.

How does soft washing of roofs work?

Soft washing is a low-pressure cleaning method used to clean roofs. It involves applying a gentle cleaning solution designed to kill algae, moss, and other growth as well as dissolve stains and dirt.

An alternative term for soft washing is “low-pressure roof cleaning.”

The solution is left on the roof for a specific time to loosen the growth and stains. Then, the roof is rinsed with low-pressure water, removing the contaminants.

Soft washing is safer for the roof and more effective than high-pressure washing. It should be done by professionals for the best results.

What PSI is used for soft washing a roof?

The pressure of the sprayer is typically set between 150 and 300 PSI, although it can vary based on the specific requirements of the job. This lower pressure is crucial in soft washing to prevent damage to the delicate roof materials.

The cleaning solution used in soft washing is a blend of biodegradable chemicals, surfactants, and detergents. These solutions are specially formulated to target and kill organic growth like algae, moss, lichens, and mildew. They also help to dissolve stains, dirt, and other contaminants on the roof.

Following the application of the cleaning solution, there is typically a dwell period during which the solution remains on the roof surface. This allows the chemicals to penetrate and break down the growth and stains, making them easier to remove.

After the dwell time, a low-pressure rinse is performed using water. The pressure is adjusted to a level that is safe for the roof material and does not cause any damage.

The rinse effectively removes the cleaning solution along with the loosened contaminants, leaving the roof clean and restored.

Why is soft washing preferred over high-pressure washing?

Soft washing is preferred over high-pressure washing for roofs because it eliminates the risk of causing damage to the roof, including dislodging shingles or tiles and driving water beneath the surface.

Soft washing is safer, reduces environmental impact, and provides longer-lasting results compared to high-pressure washing.

What chemicals are needed for soft wash roofing?

The chemicals commonly used for soft washing roofs include:

  • Sodium Hypochlorite: Sodium hypochlorite is a chlorine-based compound and is often a primary ingredient in the cleaning solution used for soft washing roofs. It acts as a bleaching agent and disinfectant, effectively killing algae, moss, lichens, and other organic growth on the roof.
  • Surfactants: Surfactants are compounds that help break down and remove dirt, stains, and contaminants. They assist in the cleaning process by improving the solution’s ability to adhere to the surface and penetrate the growth and stains.
  • Tri-sodium phosphate (TSP): Tri-sodium phosphate is a commonly used cleaning agent that helps remove stubborn stains, grease, and grime. It enhances the effectiveness of the cleaning solution by aiding in the removal of various contaminants from the roof surface.

In addition to the chemicals mentioned earlier, soft washing solutions can include various surfactants, specialty cleaners, and chemicals to enhance the cleaning process. Some examples of these chemicals and products commonly used in soft washing include:

  • Pro-Wash Degreaser
  • Max Cling Lemon Wash
  • MWE Starter Kit
  • Super Cling Citrus Wash
  • Neutra-Bleach Rinse Aid
  • Gutter Brite

These products are specifically designed for soft washing applications and can help improve the cleaning effectiveness, remove grease and grime, enhance clinging properties, and provide additional benefits such as rinsing aids or gutter cleaning solutions.

What equipment do you need for soft washing a roof?

  1. Pump sprayer: A pump sprayer is used to apply the cleaning solution to150–300 the roof surface. It should have adjustable pressure settings to maintain the recommended pressure range of 150-300 PSI for soft washing. The sprayer should also have chemical-resistant seals and components to handle the cleaning solution effectively.
  2. Nozzles and spray tips: Different types of nozzles and spray tips are used to control the spray pattern and coverage of the cleaning solution. They can be adjusted to achieve the desired application pattern and ensure an even distribution of the solution.
  3. Safety gear: Personal protective equipment (PPE) is essential for the operator’s safety during soft washing. This may include gloves, goggles or safety glasses, a respirator or mask to protect against chemical fumes or particles, and appropriate clothing to protect against chemical exposure or potential hazards during the cleaning process.
  4. Ladders or access equipment: Depending on the size and height of the roof, ladders or other access equipment may be needed for the operator to safely reach and work on the roof surface. Safety precautions, such as harnesses or fall protection measures, should be followed as required to prevent accidents.
  5. Water source: A water source is necessary to supply the pump sprayer with water for diluting the cleaning solution and rinsing the roof after the dwell time. This can be a garden hose connected to a water supply or a water tank, depending on availability and specific job requirements.

Can you rent a soft-wash power washer?

It is possible to rent a soft-wash power washer for your cleaning needs. While availability may vary depending on your location and rental providers in your area, there are rental companies that offer soft wash equipment.

Contact local equipment rental companies in your area and inquire about their offerings. Explain that you are specifically looking for soft-wash power washers or low-pressure cleaning equipment designed for soft washing.

Some rental companies specialize in providing equipment for cleaning and maintenance tasks. They may offer soft-wash power washers or have a selection of low-pressure cleaning equipment suitable for soft-washing.

It is less likely to find a soft wash power washer or specialized soft wash equipment at traditional hardware stores like Home Depot or Lowe’s. These stores primarily cater to general consumer needs and typically offer a selection of pressure washers that are more suited for high-pressure cleaning tasks than soft washing.

What are the dangers in the chemicals and equipment used

There are potential dangers associated with the chemicals and equipment used in soft washing. It’s important to be aware of these hazards and take the necessary precautions to ensure safety. Here are some potential risks:


  • Chemical irritation: The cleaning solutions used in soft washing may contain chemicals that can cause skin, eye, or respiratory irritation. It is crucial to wear appropriate personal protective equipment (PPE) such as gloves, goggles, and respirators to minimize the risk of exposure.
  • Environmental impact: Some soft washing chemicals, such as sodium hypochlorite, can be harmful to plants, aquatic life, and the environment. Care should be taken to prevent overspray or runoff into sensitive areas, and local environmental regulations should be followed


  • Pressure hazards: While soft washing uses lower pressures compared to high-pressure washing, there can still be risks associated with operating pressure equipment. High-pressure spray can cause injury if directed towards the body or if the equipment malfunctions. Following proper operating procedures and using appropriate safety measures are essential.
  • Falls and accidents: Working on roofs or using ladders to access roof surfaces can pose a risk of falls and accidents. It is crucial to use proper fall protection equipment and follow safety guidelines when working at heights.

Here’s how to mitigate the risks of soft washing

  • Read and follow the manufacturer’s instructions and safety guidelines for the chemicals and equipment used.
  • Wear appropriate PPE, including gloves, goggles or safety glasses, and respiratory protection as required.
  • Handle and store chemicals according to the manufacturer’s recommendations.
  • Use equipment that is in good working condition and properly maintained.
  • Take precautions to prevent chemical overspray or runoff into sensitive areas.
  • Ensure proper ventilation when working with chemicals in enclosed spaces.
  • Follow proper ladder safety protocols and use fall protection equipment as necessary.
  • Consider hiring professional soft washing services who have the expertise and experience to handle the chemicals and equipment safely.

What are the benefits of soft washing a roof?

Soft washing offers several advantages when it comes to cleaning and maintaining roofs.

It effectively removes and kills algae, moss, lichens, and other organic growth that can deteriorate the roof’s surface and compromise its integrity.

This helps to extend the lifespan of the roof and prevent costly repairs or replacements.

Soft washing is also a gentler method compared to high-pressure washing, reducing the risk of damage to delicate roofing materials.

Soft washing solutions are typically biodegradable and environmentally friendly, minimizing the impact on surrounding vegetation and ecosystems.

What are the drawbacks of soft washing a roof?

While soft washing has numerous benefits, there are a few drawbacks to consider.

One limitation is that soft washing may not provide immediate results.

It requires time for the cleaning solution to work and break down the organic growth.

This means that visible improvements may take a few days or weeks to become apparent.

Another drawback is the potential for residual staining.

While soft washing can effectively remove organic growth, it may not eliminate deep-set stains or discoloration caused by other factors.

In some cases, a separate stain removal treatment may be necessary.

Also, soft washing may require professional expertise and equipment, which can add to the overall cost if homeowners choose to hire a professional soft washing service.

What are the differences between roof soft washing and pressure washing?

Roof soft washing and pressure washing are two distinct methods used for cleaning roofs. Here are the key differences between the two:

  • Pressure: The primary difference lies in the pressure used during the cleaning process. Pressure washing utilizes high-pressure water spray, often exceeding 1000 PSI, to forcefully remove dirt, grime, and stains from the roof surface. In contrast, soft washing employs much lower pressure, typically ranging from 150 to 300 PSI, which is gentler on the roof and less likely to cause damage.
  • Cleaning solution: Soft washing relies on specialized cleaning solutions that are applied to the roof surface. These solutions contain biodegradable chemicals and surfactants that effectively kill and remove organic growth such as algae, moss, and lichens. Pressure washing, on the other hand, primarily relies on the force of water to clean the roof, without the use of chemical solutions.
  • Surface compatibility: Soft washing is suitable for a wide range of roofing materials, including asphalt shingles, metal roofs, tile roofs, and more. The lower pressure and use of cleaning solutions make it a safer option for delicate and sensitive roofing materials. Pressure washing, while effective for certain roof types, may not be suitable for more fragile materials as the high-pressure water spray can cause damage or dislodging of shingles, tiles, or other roofing components.
  • Cleaning effectiveness: Soft washing not only removes visible dirt and stains but also kills the underlying organic growth, ensuring a longer-lasting clean. In areas that pressure washing alone might miss, the cleaning solution seeps into pores, cracks, and crevices. Pressure washing, while effective for removing surface dirt and debris, may not eliminate the root cause of organic growth, allowing it to potentially regrow more quickly.
  • Safety: Soft washing is generally considered a safer method as it minimizes the risk of damage to the roof and surrounding areas. The lower pressure and use of appropriate cleaning solutions reduce the likelihood of accidents, surface damage, and water intrusion. Pressure washing, if not used correctly, can lead to unintended damage to the roof, dislodging of shingles, and even water infiltration into the building if not properly controlled.

Can soft washing and power washing your roof be used together?

Soft washing and power washing are two distinct methods that are typically not used together on the same roof.

Soft washing involves the use of low-pressure water spray combined with specialized cleaning solutions to effectively remove organic growth.

Power washing, on the other hand, relies on high-pressure water spray to forcefully clean surfaces.

Mixing the two methods can increase the risk of damage to the roof, especially for more delicate materials.

How to determine if you need soft wash roof cleaning

Determining if you need soft wash roof cleaning depends on several factors.

First, inspect the roof for the presence of algae, moss, lichens, or other organic growth.

These can appear as dark streaks, discoloration, or green patches on the roof surface.

If the roof has a history of organic growth or is in a shaded or humid area, it may be more susceptible to needing soft wash cleaning.

Also, consider the age and condition of the roof.

Older roofs or those showing signs of deterioration may benefit from soft washing to remove organic growth and extend their lifespan.

What are the signs that make your roof perfect for soft washing?

Several signs indicate that your roof may be a good candidate for soft washing.

If you notice black or green stains, streaks, or discoloration on the roof surface, it likely indicates the presence of algae, moss, or lichens.

Also, if the roof is located in a shaded or humid environment, it creates a favorable environment for organic growth.

Other signs include a history of recurring organic growth on the roof, a desire to improve the overall appearance of the roof, or a need to maintain the roof’s integrity and extend its lifespan.

When is roof soft wash not good for you?

While soft washing is generally a safe and effective method for cleaning roofs, there are situations where it may not be the best choice.

If your roof is in a severely deteriorated or fragile condition, soft washing may exacerbate existing damage or cause the dislodging of loose shingles or tiles.

If your roof has loose or damaged flashing, soft washing could introduce water into the building, leading to leaks or other issues.

In these cases, it is recommended to consult with a professional roofer or a soft washing expert to assess the condition of the roof and determine the most appropriate course of action.

How long does it take to soft-wash your roof?

The duration of soft washing a roof can vary depending on factors such as the size of the roof, the extent of organic growth or stains, and the efficiency of the soft washing equipment being used.

In general, soft washing a residential roof can take several hours to complete. Larger or more complex roofs may require additional time.

Also, don’t forget that some soft washing solutions require a dwell time for the chemicals to effectively break down the organic growth, which can extend the overall duration of the process.

How much does it typically cost to soft wash your roof?

The price range for soft washing a roof is typically around $0.30 to $0.75 per square foot.

If you have a 2000-square-foot home and you are looking to have the roof soft washed, you can estimate the cost based on the average price range of $0.30 to $0.75 per square foot.

Using the lower end of the price range, $0.30 per square foot, the calculation would be as follows:

2000 square feet x $0.30/square foot = $600

Therefore, the cost of soft washing a 2000-square-foot home at $0.30 per square foot would be approximately $600.

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Author: Logan

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