WE rely heavily on the treatment products that we use as it is a specific blend of the right ingredients to kill and deter moss and algae growth plus it has the right amount of surfactants to help it stay on longer and work with mother nature. Surfactant – a substance that tends to reduce the surface tension of a liquid in which it is dissolved. 

Eco Friendly! It is a “Safer” product and is a registered Organic with the OMRI. Safe to use around landscapes, gardens, plants, folliage, grass, etc. We are pretty proud of it. The main active ingredients are, salts of fatty acids. Works Amazing!

How you get the most life out of your roof, is to rely heavily on the treatment, minimize foot traffic, and minimize the amount of washing or brushing. Which is why we like to get people on a regular annual maintenance plan. 

If you are thinking about having this done, make sure no type of high pressure is going to be used and that your contractor does a thorough inspection to make sure your roof is a good candidate for a cleaning. Not all roofs will benefit from being cleaned. 

Now Let’s talk about other contractors and cleaning your roof. As a general rule, anytime a contractor wants to sell you a cleaning that involves the use of a high pressure, pressure washer, they are VERY NEW to the roof cleaning industry, don’t understand it, and should probably be avoided at all costs..

In this article, I will explain why  pressure cleaning asphalt  and the new “eco friendly” cleaning companies and chemicals that are appearing , should not be a part of the discussion when you are thinking about picking the right company.

As this industry grows here in the Portland/OR area, I am hearing more about contractors who are actually using pressure washers and bleach to clean roofs, and who are not licensed by the department of ag. Bleach is very caustic and it can be hard on the landscape and water sheds. It seems to be a mix of new companies coming into the market, and existing pressure washing companies that are  adding roof cleaning to their service for an additional revenue stream.  This is sketchy. As a company who has been doing this for 15 years, you really need to have the knowledge and experience to do the job right. 

Our area in this part of the state is pretty fortunate not to have more than a couple of the “Eco Friendly” roof cleaning companies. The claim is that the chemicals they use, which are mostly sodium hydroxide, are Eco Friendly and will not harm plants, animals or the environment. Try asking them for a copy of their MSDS (Material Safety Data Sheets) and you will get a little different story. Also, ask for their workers comp insurance, department of Agriculture license and CCB number. 

Here is the bottom line on any type of “Eco Friendly”: Hire someone who can show you all of their proper credentials and explain their process. 

Store bought chemicals and do it your selfers beware, this is a very dangerous job for many reasons. You can screw up your roof and your body by getting injured. So just please leave this up to the experts. 

Reading the warning label on some of these products will serve to convince you on just how “Eco Friendly” they are.

Funny things and ways that we have seen companies do.

A rotating surface cleaner for the ground. This device is a surface cleaner.  It is generally used to clean concrete utilizing high pressure. Underneath, you will find two high pressure nozzles attached to a rotating arm. (Picture a lawn mower blade). Please do not let anyone use one of these, unless it is for high pressure ground work only. 

Some companies are “modifying” these to do other jobs.  The cleaner will stand at the top of the roof, lower the surface cleaner down the roof pitch with a rope, and then pull it back up. Wow! Just please stop! If you see this, fire the company right away. 

The general sales pitch associated with these companies is that they have modified the machines for lower pressures or they hold the wand high and away. 

Having been around the business for over 15 years I can tell you with a fair amount of certainty, that an older structure would not withstand the onslaught from a pressure cleaning wand, or one of these machines.  Read why below.

Using a pressure washer to clean a roof does two things:

  • It lifts the shingle tabs and breaks their seal.
  • It removes the protective surface granules on the shingle.

Asphalt shingle roofing systems are usually installed as a restrained tab or a self- sealing system.  That means that each shingle has a sealant strip on it so that when they are installed correctly, each row of shingles will adhere or seal themselves to the row above and below them.

Asphalt roofing systems are designed to withstand a certain amount of wind load.  It is this self-sealing shingle system that makes you roof wind resistant and keeps your shingles from blowing off the roof during most storms.

When a pressure washer is used to clean a roof, regardless of how careful the wand wielding cleaner is, there is a high probability that some shingles are going to get lifted and this seal will be broken. This leaves your shingles “flapping in the wind” during the next storm.

You will also lose a lot of the surface granules from your shingles.  These granules play a role in protecting the shingle and helping to reflect the sun’s rays so your attic stays cool.  The older the roof, the more granules you will lose in the washing process.

Please rely heavily on the treatment, and minimize the amount of cleaning and foot traffic. 

We treat roofs from the gutter line and from the ridge to minimize foot traffic. 

They have issued a bulletin about the proper way to clean an asphalt shingle roof  that is extensively referred to by professional roof cleaners in our industry. It involves a pre inspection to see which method is best going to suit your needs based on the integrity of the roof, budget, and a few other factors.  There is no other method that is approved.  If someone is washing it using a pressure system or brushing method or one of the devices pictured above, they should always do the treatment and inspection first. It is like going to the doctor to get a checkup, and a plan for future work needed to be done.