House Washing: Pressure Washing vs. Soft Washing

House Washing

When you think of house washing you probably think of pressure washing; applying high pressured water to the house or sidewalk to remove the algae or other organic growth. Simple concept, right? The concept is right, but the results are only aesthetic and that is if you’re lucky. Read on to learn more about the differences between pressure washing vs. soft washing and how the team at Harbor Painting Co. Inc. can safely and effectively clean the exterior of your home from top to bottom.


To make sure your house washing is done properly, you should hire a company who’s staff has the training, experience and proper equipment to get the job done. Often, we are called to wash a house where the homeowner previously hired a worker from an online ad on Kijiji or a pull tab advertisement at a local gas station pump and the experience was less than desirable.


In most cases, the home is left with giant streaks on the siding that can be seen from down the road. There are two reasons that streaks are left on siding: the unnecessary use of high pressured water and oxidation. Over time, vinyl and aluminum siding becomes oxidized. This happens as the UV inhibitors applied by the factory begin to break down because of the harsh elements they experience.

An easy way to check if your siding is oxidized is by taking your finger or a clean cloth and gently running it across the surface. It is oxidized if a white chalk-like substance appears. In most cases, just because oxidation is present does not mean you’re out of luck and need to replace the siding. We use a safe application known as soft washing to remove and restore it almost as if the siding were new.


So, what is soft washing exactly? Instead of high-pressure cleaning, the soft wash application and solutions are applied at a pressure that is no more than what a garden hose produces. This low pressure makes soft washing an extremely safe way to perform house washing to the exterior of your home. Our eco-friendly and biodegradable chemicals break down oxidation allowing us to rinse it right off. While this process may take more than one application, the results are fabulous.

You may be wondering, if the pressure is no more than a garden hose, how can you reach and clean the second or third story of my home? The equipment on our trucks uses highly pressurized air to charge our water lines which pushes the water and cleaning solutions to heights upwards of 50 feet in the air. This means that we rarely have to step foot on a ladder and that, in most cases, our house washing is done safely from the ground.


Have you ever looked up at your roof and noticed that your asphalt shingles have developed dark black streaks? What you are seeing is known as Gloeocapsa magma or blue-green algae; a small group of algae spores that if left on your shingles long enough will cause significant damage.

Gloeocapsa magma breaks down the shingle by feeding on the limestone granules it’s made up of. Some side effects are:

  • Lack of protection from UV light rays

  • Shingle curling, which can result in higher air conditioning and heating bills

  • Frequent and costly roof repairs

  • Can potentially cause raised humps in your roof

Not to mention, your roof sticks out like a sore thumb amongst all of your neighbours’ houses. Our wash technicians are trained to remediate such algae growth and do so successfully on a regular basis.

Similar to our house wash process, we apply biodegradable chemicals to your roof at low pressure, most of the time from ground level. This process successfully removes algae, grit, grime, moss, and soot from your shingles. The Asphalt Roofing Manufacturers Association (ARMA) recommends this process to keep your roof in good condition and in some cases to stay compliant with many of their warranties. We follow their recommendation of using our proprietary mixture of sodium hypochlorite and powerful soaps. You should never use pressure that is greater than the strength of a garden hose to clean your roof.


The cherry on top of a complete house wash is the gutter brightening. When your siding gets washed, we can apply a solution to your eaves and soffits to kill algae and mildew buildup which makes a huge difference. However, you can take it one step further and brighten your gutters to make them look brand new.

While a quick wash can make your gutters look new, at a closer look you will likely notice dark vertical stripes. In the house washing industry, we refer to these as “tiger stripes.” Tiger stripes appear over time from pollution and dirt build-up around the lip of the eavestrough. After some time, the precipitation and runoff continue to follow the same path, leaving behind dark stripes.

You may think that the original finish has been removed from the aluminum, but that is likely not the case. Our team can effectively remove these stripes and brighten your gutters by applying a biodegradable concentrated cleaner with handheld pump sprayers. After a light scrub with a soft-bristled brush, your eavestroughs and soffits will look brand new!


Simply put, if algaecides and fungicides are not applied to your house or roof when it’s being washed, the root of the problem is not being taken care of. Washing with only high pressures to remove organic growth without killing its root is like expecting your hair not to grow back after getting a haircut.

Pressure washing your house will not solve your algae problems. In fact, it will only speed up the growing process and in many cases leave you with a bigger problem than you started with.

If you or someone in your home suffers from seasonal allergies, a good place to start fighting the problem is on the exterior of your home by killing all algae, mold and mildew growing and safely removing it without spreading the spores around. While our exterior washing services create a type of aesthetic satisfaction for your home, our goal is to create healthy and safe environments for everyone around us.


You can rest assured that Harbor Painting Co. Inc. has the right equipment and expertise to safely and effectively clean the exterior of your home, roof and gutters. To learn more about our pressure washing and soft washing services and to request a quote, contact us today.