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Soft Wash Roof Cleaning | Comprehensive Guide

soft wash roof cleaning

There are many ways to clean a roof, but an effective and environmentally friendly way is with a soft wash.

Soft washing can remove dirt, mold, mildew and lichen from the surface of your roof. This type of cleaning will not damage shingles or gutters like other methods may do.

What is Soft Wash Roof Cleaning?

Soft wash roof cleaning is a safe, cost effective way to clean your roof without damaging your roof.

The soft wash system uses biodegradable liquid soap that loosens dirt buildup and allows for it to be easily rinsed away.

Soft wash roof cleaning provides effective and affordable roof cleaning.

Some use a high-powered sprayer that releases a soapy mixture through your roof’s drain spouts, which is pulled by gravity back down the exterior surface of the building where it loosens and carries away dirt and debris.

Soft wash roof cleaning is a safer alternative to pressure washing because the mixture used only contains soap and water, which has no adverse effects on your shingles or gutters.

The process is completely safe for you, your family, and your landscaping!

Soft Washing your Roof

Why should I have my roof cleaned?

Roof cleaning is necessary whenever your roof needs to be refreshed. All roofs get dirty over time, especially the shingle roofs that are found throughout Southern California.

This dirt buildup makes it harder for water to flow through your drain system, which can cause heavy backups and potential flooding under certain circumstances.

Other problems caused by dirty roofs include moss and lichen growth, which can create an uneven surface for water to run off of.

The dirt buildup also encourages the development of mold and mildew, which often creates a foul order.

These unhealthful conditions can cause damage not only to your roof but to your family as well!

A soft wash roof cleaning that is done by professionals has multiple benefits.

From the cleaning itself to the fact that you do not have to get on a ladder or use roofing equipment, there are many advantages available in hiring a professional for this job.

Soft wash roof cleaning is also better for your home’s surroundings!

A soft wash method uses about 90% less water than a high-pressure cleaning system, which decreases the risk of flooding and damage to your landscaping.

Why soft wash your roof?

The most common reason to have a roof cleaned is because of black algae growth.

The black spots are actually photosynthetic organisms which contain chlorophyll in the same way plants do.

When it comes in contact with water, sunlight and nutrients found abundantly in our coastal environment, algae begins to grow.

The algae can form a slimy film on the surface of your roof, making it slippery and an accident waiting to happen.

As well as being unsightly, algae can also block drainage outlets which in turn may result in water pooling on the roof and leakages in a property.

How often should you clean your roof?

It really depends on the environment where your property is located.

If you live near the water it is likely that black algae will start to grow on your roof within months of cleaning, whereas if you are further inland it may take years before you need another clean.

The most effective way to control black algae growth is by staying on top of your roof cleaning.

Roof cleaning is an ongoing process, but by removing the build up of algae before it has a chance to grow you will be ensuring that your roof stays clean.

What are the benefits?

There are many advantages that come with using a soft wash method for roof cleaning.  

  • The first benefit is that this type of service does not damage your roof.
    • It is a gentle and effective way to clean roofs that won’t cause any damage like high-pressure cleaners can.
  • Soft washing also helps to keep algae and moss from growing back.
    • The soft wash team will go through all the necessary steps so you won’t need to have it done again for years.
  • Soft washing your roof can also speed up the drying process which means you won’t have to stay off of the roof as long and it will cut down on water pooling.

Are there chemicals involved in Soft wash Roof Cleaning?

Chemicals are a part of the soft wash roof cleaning process. Cleaning a roof is a science, and science requires chemistry.

The specific types of chemicals used vary from company to company, but some commonly used chemicals can include bleach, vinegar, acids, soaps, biocides and surfactants.

Surfactants are used to help the cleaning solution spread over the surface. They are also useful in corrosion prevention. Surfactants can be categorized into two types, cationic and anionic.

Cationic surfactants have a positive charge, while anionic surfactants have a negative charge.

Using different types of surfactants, depending on the intended cleaning application, allows for better chemical adhesion.

Cleaning chemicals are used to remove stains and discoloration from roofs. Stains can be very difficult to remove if not treated properly with the right mixture of chemicals.

Some roofing stains are actually living organisms, like algae. These can be removed by using an acid or an algaecide.

Algae itself is not harmful to humans, but it can pose problems for roofs if left untreated.

Common chemicals used for soft wash roof cleaning

The most common chemicals used in residential soft wash roof cleaning include:

  • Caustic (sodium hydroxide) –  This is the strongest of the chemicals, and should only be used by experienced professionals.
    • It can burn skin on contact, so safety precautions are important to follow when using caustic.
  • Surfactants (detergents) – This chemical helps break down dirt and stains, making them easier to wash away with water.
    • Surfactants also help keep roofs clean by preventing the growth of new stains.
    • Surfactants are anionic, non-ionic and cationic in nature.
  • Bleach – This is a common choice for many soft wash roof cleaners.
    • Bleach’s strong oxidizing properties help break down tough stains from algae, fungi and lichens that grow on roofs when they’re left untreated.
    • Bleach also helps prevent new stains from growing on roofs as it kills mold spores and algae cells.
  • Water – Although a strong scrubbing brush will only require water, there are some stains that need more help.
    • Sometimes multiple chemicals are combined to create a strong cleaning solution capable of removing difficult stains.
  • Vinegar – This is commonly used as it tends to be less expensive than bleach and acids, but is still very effective at helping remove algae and fungi stains on roofs.
    • Vinegar is also safe for most green vegetation, which can be important when working around plants and trees.
  • Hydrochloric acid –  This is another option for soft wash roof cleaners who want to use acids.
    • Hydrochloric acid can be diluted with water, but it’s important to make sure the solution isn’t too strong.
    • This type of acid will need to be used carefully because it can burn skin and damage clothing if it comes in contact.
  • Biocides – Biocides are chemicals used to kill living organisms, which means they can also kill mold spores, algae cells and other microorganisms that grow on roofs.
    • Some biocides are naturally occurring, while others are created in a lab.
  • Soaps – Soft wash roof cleaners use soaps for three main purposes: 1) as an extra surfactant to help break down stains, 2) as a natural source of biodegradable enzymes and 3) to help kill algae cells.
  • Algaecides – As their name suggests, algaecides are chemicals used to help control the growth of algae on roofs.
    • These types of chemicals use copper sulfate salts to prevent new algae from growing on roofs.
  • Trisodium phosphate (TSP) –  This is a strong chemical that can remove difficult stains easily.
    • It needs to be diluted before being used, but one of the benefits of TSP is it doesn’t have residual properties.
  • Sodium carbonate peroxyhydrate (SCPH) – SCPH also functions as an algaecide, but it’s commonly used for roof washing because it is less corrosive than other chemicals.

5 Steps for Soft Wash Roof Cleaning

1) Safety first – Make sure to wear proper safety gear when cleaning roofs. This includes long sleeves, rubber gloves, eye protection and shoe coverings.

2) Prepare the roof – It’s important to not just spray chemicals randomly over roof surfaces. A slow and methodical approach is best to make sure the chemicals stay in place.

3) Apply the chemicals – Use a spray applicator or high-pressure washer with a brush nozzle attached to provide scrubbing power for tough stains.

4) Wait 15 minutes – Soft wash roof cleaning requires patience as it takes time for the chemicals to do their job. If the chemicals are applied when it’s too hot outside, they won’t work as effectively.

5) Rinse with water – Once the old grime has been broken down, it needs to be rinsed off completely with fresh water. This will ensure that no residue is left on the roof so algae and mold can’t start growing again.

There are many chemicals available for soft wash roof cleaning, but it’s important to select the right ones to avoid damage or injury.


Soft wash Roof Cleaning is the safest and most effective way to remove dirt and stains on any roof.

Chemicals are used for soft washing roofs and they have a number of benefits.

Some may need to be combined or diluted before being applied on the roof, but this process is relatively straightforward as long as people use proper safety equipment.

Roof Cleaning with a Soft Wash