What Is Soft Washing a Roof?

What Is Soft Washing a Roof?

It’s above you every day, but you rarely give it a second thought. What is it? It’s your roof.

Your roof provides you with defence against wind, rain, snow, hail and heat. Every day your roof is exposed to the elements, all of which contribute to its damage and deterioration over the years.

The primary cause of roof problems is a poorly maintained roof. As one of the largest parts of your house, it requires regular inspection, maintenance, cleaning and potential repairs. It is by far the most vulnerable part of your home.

Its lifespan can be shortened dramatically if neglected, however, with proper cleaning, your roof can last anywhere between 15 to 30 years.

Why is roof cleaning so important, you may ask? Let’s look at some of the reasons below:

Cleaning Increases The Lifespan of Your Roof

Your roof is constantly being exposed to all kinds of conditions, so it is very important that you provide your roof with cleaning and maintenance to avoid major damages.

This cleaning also lengthens the life of your roof. Roof cleaning can also mean the difference between a repair and a replacement when there is a problem, minimizing future or unexpected costs.

How Often Should You Have Your Roof Inspected and Maintained?

Well, that can depend on several factors. The age of the roof, weather conditions that occur locally, and any problems identified during previous inspections.

Even if your roof is newer or hasn’t had any issues, it’s always a good idea to have it inspected at least once every few years. Your warranty doesn’t completely protect you.

A warranty can give you a false sense of security, but it’s important to remember that just because your roof came with a warranty it doesn’t mean that it will be repaired or replaced with no questions asked.

Like other legal documents, every warranty will have exceptions and limits, which also means that warranties can have limited value.

When you are dealing with a roof warranty, it is important to remember that there are many factors at stake.

Not all roof warranties are the same. Many of these warranties can easily be voided if materials have been installed incorrectly, or if the damage is caused by something as innocent as installing a roof-top satellite dish. Because of this, it’s extremely important to check all the details of your warranty before undertaking any sort of installation to your roof.

Many roofing companies and roofing material manufacturers require you to get a professional inspection every few years, or after a major weather event, for their warranty to remain active. If you’re unable to show proof that your roof has been maintained, you may run into problems if you try to claim your warranty.

Your roof is part of your house’s appeal. You want your house to look good both inside and out, right? Even with this in mind, people often forget their roof because subconsciously, they take it for granted. It’s above their heads, so it isn’t something that they would usually think about.

Your roof has an important charm and appeal, that your neighbours and those wanting to move into your area will notice. As anyone in the housing market will tell you, an attractive exterior can make or break a house sale.

Clogged gutters can cause rain and snow to not drain properly, possibly ruining the surrounding landscape as well as the gutters themselves. Roof mosses or algae can build up, can prematurely age your roof and cause ugly black streaks that can be unsightly and even off-putting for some people.

Many of these problems can be fixed by simple maintenance tasks such as roof cleaning and debris removal using the process of Soft Washing. The purpose of this article is to look into a little more detail, including:


The Process of Soft Washing

Soft Washing is best described as an exterior cleaning method that removes grime and other build-ups that may have built up over time. It has distinct differences to a pressure washing system, a Soft Wash system uses a chemical solution to remove the grime on exterior surfaces.

It is also a cleaning method which uses low pressure and specialised solutions, usually incorporating some form of bleach or other detergents, water, and sometimes a surfactant, to safely remove organic build-up or stains from roofs and other building exteriors.

Due to the differences in the approach, Soft Washing differentiates from other methods, such as regular Power Washing or Jet Washing. The Asphalt Roofing Manufacturers Association recommends a low-pressure, bleach or detergent assisted washing as the preferred method for cleaning asphalt roofs in particular, this is to prevent damage to the shingles.

Soft Washing typically uses an electrical agricultural sprayer to apply a water-based, biodegradable detergent cleaning solution to kill:

  • Mould
  • Mildew
  • Bacteria
  • Algae
  • Fungus
  • Moss
  • Lichens
  • And more,

on the exterior of a house and building surfaces.

Soft Washing equipment is distinctly different from regular power or pressure washing equipment. The electric diaphragm pump applies the cleaning solution at far lower pressures, around 40-80 PSI.

The equipment used for Soft Washing may also make use of telescopic handle extensions so that the cleaning solution can be easily applied to roof eaves, without the added assistance of the higher pressures.

High-pressure cleaning of ageing roofs is a very aggressive solution which can cause substantial damage, so it is generally not recommended by roofing material manufacturers or roofing associations to help protect the integrity of roofing materials.

Soft Washing is a gentle solution to roof cleaning and restoration, whilst high-pressure blasting can subject a roof to damage without removing the root cause of infection. A low pressure, Soft Washing roof clean solution can leave roofs clear from algae and other grimy build-ups for months and even years to come.

Several different methods can be used when Soft Washing a roof. These vary depending on the severity of the infection to the roof, and the size of the job in hand.

If moss is needed to be removed, you would need to cover areas around the roof with suitable protection ready for the moss removing process, then start to remove the deposits of moss manually using various, dedicated and specialist hand tools.

Once you are satisfied the bulk of the moss has been removed manually, you would then apply the Soft Wash treatment to the roof tiles using specialist Soft Wash equipment. This is when the Soft Washing technique gets to work and starts to kill any remaining moss, algae and lichens that are still on the roof.

Then when you have completed the initial roof clean, you would then clear out the gutters removing all remaining debris from them that may have fallen during the initial cleaning of the roof. ​Not only will Soft Washing clean and restore your roof without the worry of any damage occurring, but it will also protect the roof from any regrowth for many months, even years to come.

What Are The Benefits of Soft Washing?

The Soft Washing approach can completely kill any unwanted organisms growing on your roof. It should not void the warranty of the roof if the application is carried out properly using low pressures – this low pressure is the equivalent to a garden hose pressure, therefore ensuring the integrity of the roof for many years to come.

Soft Washing is one of the best solutions to maintaining a clean roof for an extended period.

Gloeocapsa Magma (algae) can be a very common problem on roofs which can often leave signature black streaks all over your shingles, especially on older roofs.

This substance thrives in particularly well in hot and humid temperatures, and then it begins to spread out, having a destructive effect on your roof. It feeds off the moisture that certain types of shingles hold on to.

Whilst the roof contains this form of algae, it can begin to lose its ability to reflect UV rays and eventually rots the shingles. This can, in turn, affect roofs severely and can even take as many as up to 10 years off the life of a roof.

Soft Washing is the only way to effectively remove this form of algae without damaging the shingles and voiding any warranty.

Pressure washing a roof, even at lower pressures, could potentially void your warranty and may even cause a granular loss in the tiles and shingles. This means that the integrity of the roof tiles will be compromised due to damage from the intense pressure of the water. Leading to the tiles needing to be replaced.

In addition to the above, power-washing only cleans the actual surface of the roof without removing the root systems of the algae and other pests that have grown in, around, and under the tiles. Using Soft Washing techniques eliminates all plant, fungal, and bacterial life and any dirt and grime from the roof safely, returning it to its original colour with much greater reduced risk of damage to the roofing materials.

Soft Washing was initially created as a cleaning technique for safely removing algae stains from shingle roofs. By nature, shingle roofs are designed to make a home’s roofing structure more resistant to damage from the elements, in turn protecting the inside of the home.

The shingle roofing system is made up generally of three parts, fibreglass sheets, petroleum adhesive and ceramic or stone aggregate. These shingles are placed on top of a petroleum-based tar paper, more commonly referred to as “roofing felt”. This protects the wood sheeting or deck of the roof from moisture. All of this roofing anatomy quickly degrades, except for the topmost and most important ingredient of a roofing shingle system, known as the aggregate.

Roofing aggregate is pressed into the hot asphalt or petroleum-based adhesive on top of a shingle and it becomes a protective barrier for nature to attack and slowly eat away during a shingle roof’s life cycle. It largely protects the roofing system from two weathering elements: rain and storms, and also UV degradation. The aggregate reflects the sun’s rays from the roof and over time is designed to weather away little by little, completing the service life of the shingle roof system. This, in many cases, takes anywhere up and over 30 years.

Something to think about before starting any form of roofing maintenance or cleaning project is would include how long you plan to live in the home. If long-term, think more carefully about a process that will effectively kill any form of growth on your roof and keep it off, including an effective Soft Washing approach. If you’re looking at staying in your home more short-term (if you are looking at moving, renting out or selling the home), then you may want to choose a more cosmetic approach.

Can you DIY with Soft Washing, or do You Need a Pro?

As a general rule of thumb, it would probably be recommended that you hire a professional to clean your roof. This is due to the consideration of the inherent risks in this type of work. Such as working at height for example. Although this is not necessarily the only option in all cases.

Before undertaking most forms of DIY project, there are a few things to think about and decisions that should be made by the homeowner. If the homeowner is fit and willing, it may be a worthwhile and somewhat rewarding DIY project. If you do decide to perform Soft Washing on your roof yourself, you need to make sure you take all of the necessary safety precautions. Specifically, a roof harness and an anchor should be used, especially if you are working on any type of sloped roof.

A helmet, eye protection and other personal protective equipment (PPE) should also be worn – particularly during the process whereby the chemicals are to be distributed. Another serious consideration to be made is that this shouldn’t be the type of roof cleaning project that you should be carrying out alone.

If you are determined about undertaking this type of project yourself (whether that is for economic reasons, purely the sense of accomplishment or just the sheer enjoyment of being outdoors) be sure to plan the project thoroughly and make sure you enlist the help of at least one other person.

Benefits of Doing it Yourself And How to Do It

As we have already said, one of the benefits of completing the Soft Washing project yourself is the economics of the project.

Should you be planning on staying in your home for a considerable amount of time the initial outlay of the equipment may well be costly, once you have factored in the hardware needed, the chemicals, safety equipment etc.

Split this by the number of times that you would potentially complete the project over the lifetime of an average mortgage, say 25 years, it could reduce the average cost per treatment considerably. Professional roof cleaners can charge hundreds of pounds, with the bigger the size of the roof, the more you’ll spend. On top of that, they’ll have to repeat the cleaning every few years.

If your roof slope isn’t too steep and you’re comfortable working on it, you can clean it yourself and save yourself quite a large amount of money. As a minimum, you’ll need a full-body harness, a garden sprayer, a garden hose and a nontoxic, noncorrosive roof-cleaning chemical as. Some manufacturers sell a special tool applicator and rinsing tool, but if the staining isn’t severe, you may not need them.

Another benefit to note would be the sense of accomplishment. Looking up at your roof and thinking…

“I did that”

…with a sense of pride, and a great big smile on your face.

Or maybe you’re just the type of person that loves being outdoors and getting your hands dirty. There may well be other reasons for you to consider taking on such a big project.

But now you need to know how to complete it.

You need to start by making sure you use the correct chemicals and tools for the task at hand. If you search online, you’ll see hundreds of posts on roof-cleaning methods. In less than 10 minutes, you’ll sign off convinced that all you need is a few gallons of household bleach and a power washer set at its lowest setting.

That’s definitely not the best approach. Even at low pressure, a power washer can seriously damage shingles as we have already mentioned.

Plus, chlorine bleach is a corrosive agent that can damage metal roof flashings, gutters and downspouts.

It can lighten the colour of your roof and “bleach” the colour out of anything the overspray contacts, which isn’t going to be great for those roof tiles that don’t need as much attention as the others.

The runoff can harm plants. And there’s another downside to using Bleach. Whilst chlorine bleach may kill the top layer of algae and lighten the stains, it doesn’t actually kill the underlying algae.

It’s that allows the algae colony gets right back to work. Making its reappearance in a much shorter time frame. Sodium hydroxide (lye) products, on the other hand, work better than a Chlorine bleach and are less harmful to vegetation. But they are also corrosive, and using them requires you to don full protective gear.

When looking, make sure that you look for a roof-cleaning product that’s noncorrosive and safe for the environment too. A basic list of the equipment that you would need to get you started are below.

Materials Checklist

  • A full-body safety harness with roof anchor
  • Helmet
  • Eye protectors
  • Face mask
  • Rubber gloves
  • Handheld tools such as scrapers
  • Garden hose
  • Garden spray nozzle
  • Sodium Hydroxide (lye)
  • Non-corrosive roof cleaner
  • An optional, supplemental water pump (if more pressure is needed for higher to reach spots).

Now you’ve got your tools, where do you start? You need to try and plan the right day, then prepare the area. Check the weather forecast and choose a cool or overcast day with little to no wind so the spray hits your shingles or tiles, not the neighbours’.

These conditions will allow the cleaning solution to soak deep into the algae colonies without evaporating too quickly.

Letting the solution do its job, all while ensuring you get a longer time frame between having to Soft Washing. Next, repair any loose shingles or flashings, and clean the gutters and downspouts so they can drain freely. Allowing any excess solution runoff, or rinsing water to disperse quickly and safely without any obstruction.

Once this is complete, begin to prepare the area by moving lawn furniture and covering vegetation, because you’re going to have some form of overspray. Even though the product we’ve chosen isn’t going to be toxic, the runoff can still be pretty messy. So, a little prep work will save you clean-up time later.

Once you’ve cleared any lawn furniture, covered any that cannot be moved and covered any vegetation, we are ready to begin.

Start by removing any large pieces of moss, algae and other growths, using your handheld tools, being careful not to cause any damage to the roof tiles and aggregates underneath.

Once this step is fully completed, carefully remove and discard the excess debris, again to save yourself clean up time later. Once complete, you’ll need to soak the roof tiles and shingles. Saturate a large area of shingles with the sodium hydroxide solution.

Start at the bottom row and work your way back up to the peak. Spray until you see runoff. Respray any areas that dry out.

Third step, we need to blast off all the grime.

Use the rinsing tool in a forward-and-back motion as if you’re vacuuming. That places the water jets at the correct angle to spray off any dead algae colonies.

Mix the solution with water being sure to follow the manufacturer’s instructions (a gallon covers about 700 to 900 sq. ft). Pour it into a pump sprayer, strap yourself into a full-body harness, tie it down and climb to the roof.

Before applying the cleaner, spray the roof with water to cool it down if it’s a warmer day. That’ll help to prevent the cleaner from drying out too quickly. Then spray the cleaner onto the shingles.

Wait about 20 minutes, then rinse.

If the staining is fairly light, you can rinse off the cleaning solution with just a garden hose sprayer. But go slowly and use even strokes. If you don’t, you’ll find that you end up with clean patches that were rinsed properly alongside not as clean patches that you skipped over too quickly.

For severely stained roofs, a garden nozzle won’t exert enough pressure to dislodge the stains. In that case, you’ll probably want to invest in hiring a specialised rinsing tool.

Now we need to make sure we prevent regrowth.

Depending on weather conditions, you can expect algae regrowth from anywhere as little as a few months up to a year. There are two ways to slow the regrowth process. The first is to install zinc or copper strips along the entire ridge. In theory, this is because rainwater picks up algae-killing ions in the metals, then spreads them over the roof.

In reality, the protection can fall short because algae can still feed off the humidity when it’s not raining. But you don’t have a lot to lose by trying it.

Another method is to spray on a coating of a stain-blocking solution.

A stain-blocking product can give you up to three years of protection from algae. If you decide to try it, apply it as soon as possible after you’ve cleaned the roof as this way gives the solution a quicker time to get to work in preventing regrowth.

Whether you install the metallic strips or apply the stain-blocking solutions, you’re still going to experience algae regrowth sometime down the road. Think of this project as an ongoing pest prevention solution. Make sure you get back up on your roof and clean it early enough so that any of the stains or regrowth don’t set in permanently.

Downsides to Doing it Yourself And The Benefits of Hiring Someone

The obvious starting point here would be the cost of the initial purchase of any, or all of the tools, chemical solutions, PPE, Plant or other equipment hire. You also need to consider whether this would be needed again for future treatments of Soft Washing.

Sure, some of this will be able to be reused such as Helmets or a Full-Body safety Harness for example. But in some cases, you may need to go to the added expense of hiring out scaffolding to ensure your safety.

If your regular hose doesn’t carry a strong enough water pressure to access those hard to reach places, to carry out an effective Soft Washing treatment yourself you will now need to hire out an additional water pump.

Chemical solutions will likely need to be replaced after each time the Soft Washing has been completed. Unless the shelf life on the chemicals lasts until next time you plan on carrying out another treatment of Soft Washing.

What has started as an economic do it yourself project, has now run into similar, if not greater costs than hiring a company to come and carry out the work on your behalf. Coupled with the economic cost, there is also the added time it takes you to complete the project, not only for yourself but for the person that you have recruited to assist you.

For an untrained individual, this is not likely to be a quick job either. It will probably take you the majority of a day to complete, potentially much longer – that’s providing that you get the right weather two days in a row to be able to finish the project properly.

Can your assistant spare two days to be able to help you? Or do you need to ask someone else for the following day? And yes, there are a couple of other downsides to Soft Washing your roof yourself.

Unfortunately, when you do not know the correct techniques and washing methods you need to use, serious damage can be done. Something else to think about before making your roof Soft Washing a DIY project are:

Lost shingle granules on the roof tiles. If you wash the roof too aggressively the shingle granules that are there to protect them from the sunlight and other elements, can become dislodged.

Unfortunately, scrubbing the roof with a brush or other cleaning tools will break apart these granules. You should never casually clean a roof with tools from around the house, always make sure you have the correct tools to do the job for you. This will save you from needing to replace your biggest investment any sooner than you should really need to.

Roof materials are not designed to be pressure washed with an average pressure washer. The pressure is simply too powerful, even on the lowest power setting. Soft Washing takes the right tools and techniques that are designed for the job.

Do not be tempted to try to pressure wash a roof like you would do a fence or a patio, as doing so could cause excessive damage to surface tiles or shingles, while also creating moisture damage and exposing the roof to further issues.

Benefits of Hiring Someone

Rather than tackling these problems yourself, you can save time and potentially prevent yourself a lot of trouble by hiring a professional Soft Washing service to undertake your project for you.

They will take care of everything and leave your roof looking as great as the day it was first installed. It’s fair to say that most people know that their roofs should be cleaned every now and again, but this doesn’t mean that they should necessarily try to clean it themselves.

Whilst it is admirable to have the spirit and desire to go for the DIY approach, it’s not always the smart option.

The risk to your home and yourself can be just too great to risk.

Some of best reasons to hire a roof cleaning company:

It’s much safer for you and your family.

Safety should by far be one of the biggest reasons to hire a professional roof cleaning company. Roofing is reportedly the sixth-riskiest job there is out there. And with so many accidents occurring to highly trained professionals, that have had extensive training in dealing with roofs, you can imagine just how dangerous it is for an untrained, yet enthusiastic and proficient expert in DIY. Professional roof cleaning might be more expensive than doing it yourself in the short term, but factoring in safety is definitely worth the cost.

Professionals will more than likely do a better job. 

Without the same professional training or the same high quality, professional equipment, your results aren’t going to be as good as a trained professional roof cleaner.

And nor should you reasonably expect them to be. 

Highly trained professional roof cleaning personnel know what they’re doing and they’ve got years of experience.

They’ve got the tools to make the job quicker, easier and more efficient. 

Professional cleaning companies have invested money in their equipment and their employees. The high-level tools they use allow them to consistently get great results, while still working quickly.

Please don’t make the mistake of thinking you could do it faster, or cheaper, yourself. Ultimately, you end up saving yourself from a lot of hassle and expense by hiring a professional.

Finding a Soft Washing Expert

As with any tradesperson required for a project, you will need to find someone that you consider both reliable and trustworthy to undertake the work on your behalf.

There are various factors to consider before hiring a professional to complete the Soft Washing of your roof.

Here are a few criteria that you may wish to consider;

Check for Reviews

Always read customer reviews before working with a new contractor or cleaning company. This will give you a great insight into the level of customer service and the quality of the work from people who have worked with the company previously.

Do you Plan on Using a Local or National Company?

There will be a vast array of business that can assist you in your quest to Soft Wash your roof. These will range from local businesses, who may offer a much more friendly service, and they may also be more willing to negotiate the price and more flexible with timings of the project, too much larger National companies.

Many people feel they trust larger more National companies more due to their access to more contractors who may be available on a quicker time frame.

Check the Company Website

One of the best ways to help you decide if a company is right for you to work with is to simply check out the company’s website. It should provide lots of information relating to how they price up a job, to reviews from previous customers. They may even have a blog, with posts detailing the type of work that you need undertaking. Also demonstrating their knowledge base, and the fact that they are willing to help their customers.

Compare Quotes

Before picking your Soft Wash cleaning contractor, it is a good idea to obtain a few different quotes from various reputable companies that you have found during your research. It will give you a clearer idea of how much the job should cost, indicating that you are getting quotes in a fair market.

When comparing quotes, it is essential to check that they all contain the correct information including;

  • Has the contractor clearly outlined the job, taking into account all of your requirements?
  • Are all of the required services and materials listed clearly to prevent any surprises down the line?
  • Are all the costs clearly highlighted?
  • Has the contractor indicated how and when they are expecting payment?
  • Is the work guaranteed, insured, or protected by any warranty, and if so, for how long?
  • Is the contractor protected by having the relevant levels of insurance? And is your home protected if something does go wrong?
  • Are going to be expected to cover any additional costs such as travelling or parking?
  • Are there any other costs relating to the removal and safe disposal of any waste products?

After you’ve selected a company, there are some additional further steps to consider before they start work on your roof.

  • Ask for two recent references. Call those references to confirm that they had the work that has been stated done and that they were satisfied with the end results.
  • Request to see the contractors’ insurance information. Anyone that is getting on your roof, as a bare minimum should at least have public liability insurance, and additionally ideally an employee liability insurance policy. If they cannot provide copies of either of these then there may be a chance that they are not operating a legitimate business and it is simply not worth the risk in allowing them to work on your roof.
  • Ask for the company’s safety plan for your home. Do they plan to use harnesses? Will they tie off their employees on the roof? If they aren’t willing to take care of their own team, how much care do you think they will give your roof?
  • Make sure your home is ready for the scheduled work to be done.
  • Ensure that the contractor has easy access to a water tap, preferably on the outside of your home if at all possible.
  • Make sure you are home upon completion of the work so you can walk the property with the contractor and make sure everything is done and completed to your expectations and there is a follow-up date for any work that needs to be finalised.


Whilst the thought of Soft Washing your roof may not sound like one of the most exciting household chores that you can think of, it can definitely mean that you can avoid serious and untold damage to your home or even unforeseen costs in the future.

Having a good Soft Washing care program in place for your roof can leave you to enjoy your home with the peace of mind knowing that your structure is protected.

We hope this information comes in helpful for you.