Testimonial

"I just wanted to send a note of thanks for the superior service we received from Contrast Cleaning.

I was impressed with the speed of your response to my inquiry about roof cleaning. Attaching a copy of your business license with the estimate increased my faith that I was dealing with an above-board firm. The estimator was pleasant and efficient and must have relayed our home’s particulars to you quickly, as the estimate hit my inbox very fast. I appreciated your efforts in keeping me informed via phone calls and emails.

With regards to the cleaning, your technician added to our satisfaction. Arriving in a Contrast Cleaning t-shirt, it shows your firm is striving to make a good impression. He was courteous and thorough in explaining what to expect and the cleaning itself.
Many thanks for a job well done! We will definitely seek you out again when the need arises and will recommend Contrast Cleaning to friends and family. I wish you all continued success!

Kind regards,
Cheryl"

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Pressure Washing in Portland

Roof Cleaning

Living in the Pacific Northwest means that having moss on your roof is virtually inevitable. Moss typically grows on the north sides of the roof structure and also anywhere shade is prevalent. Heavy moss can compromise the integrity of your roof shingles and thus cause damage to your roof.

before roof cleaning (left) and after roof cleaning (right)

Roof Cleaning/Moss Removal

There are a number different types of moss killing products on the market. Placing these products on your roof will effectively kill the moss but will not remove it. They will only serve to turn the live, green moss to a dead, brown moss that will still be attached to your roof.

There are essentially only two processes that remove moss from your roof: brushing and pressure washing.

Brushing the moss off your roof typically involves the use of hard bristle brushes or brooms. It is very labor intensive and takes more time than pressure washing. It is also a much less efficient cleaning method. Much of the dirt that is in place to hold the moss is left behind. This provides a welcome environment for the next season’s moss spores that will attach to your roof to grow.

Pressure washing the moss off of you roof using a low pressure has many advantages. It completely removes any traces of dirt or moss from your roof, leaving only a clean roof behind. It is less labor intensive, and also less abrasive on your shingles.

Here are the Pros and Cons to each method:

Brushing
Pros – Removes most moss from roof; provides an alternative to those who do not want their roof pressure washed; less mess involved in moss removal.

Cons – Less effective total cleaning; more labor intensive; more expensive; more abrasive on roof shingles vs. power washing.

Pressure Washing
Pros – Removes moss completely from roof; more effective total cleaning; less labor intensive; less expensive; less abrasive to your roof shingles; longer lasting results.

Cons – Un-trained technicians could damage your roof; messier cleaning process.

before roof pressure washing (left) and after (right)

At Contrast Cleaning Services, we will clean your roof according to the method that you prefer (brushing or power washing). We do prefer, however, to clean roofs by pressure washing. We believe that not only do the pros outweigh the cons vs. the brushing method, but pressure washing just makes more sense. Why? Because we think of it in just the same way as we think about cleaning off anything else. You wouldn’t want to brush remove dirt and soil from your car, driveway, or siding. Pressure washing gets the job done much faster and much more efficiently. Our technicians are carefully trained to gently remove the moss from your roof, providing you with peace of mind.

before moss removal (left) and after moss removal (right)

Roof Moss Treatment/Prevention

It is possible to keep moss from growing on your roof. The best thing you can do to keep moss from growing on your roof is to keep it clean and to treat it with moss inhibitor once or twice a year. Moss needs shade and moisture to grow. If it is possible for you to keep these two things off of your roof, you will have less moss growth. Keep debris off your roof to keep it as dry as possible. You can trim trees back, but that could be expensive, and most of us like some shade on our homes in the summertime.

If you have moss on your roof, it will need to be totally removed before applying a moss treatment (otherwise it will only serve to turn your green moss brown). After we completely remove the moss, we will apply a moss inhibitor treatment to prevent future moss growth. Having us come back out once a year to reapply the inhibitor is the cheapest and most efficient method of keeping your roof moss free.

There are a few different methods of prevention that are effective in prohibiting moss growth: Zinc Strips, Bleach, and Zinc Sulfate.

Types of Treatment
Zinc Strips can be effective at preventing moss from returning to your roof. The catch is that they only prevent moss from growing for about three to five feet below the strip. This means that most roofs will need two or three rows of it stretching across the width of your roof. Most homeowners aren’t willing to do this because of its aesthetic incapacities. In other words, it doesn’t look very good.

Bleach is a common outdoor cleaner. It is sold in most products that are used to clean things outside. Bleach is an effective moss killer. However, it is more of a temporary fix, than a permanent one. It fails as a long lasting preventive treatment, but is effective at killing moss quickly.

Zinc Sulfate is a powder that is sprinkled on your roof or mixed with water and sprayed on. In our experience, it is more effective when applied as a powder. Zinc Sulfate powder does not kill the moss as quickly as bleach will, however, it is much more effective as a long term moss prevention method. Its only drawback is that it is not safe for the environment when it is used in large quantities. For this reason we do not prefer to apply it mixed with water and sprayed on, as a greater quantity of zinc is used unnecessarily, and this water mixture then drains down your gutters and into the storm drain system. We have found the zinc sulfate to be effective in small amounts. Therefore we apply it conservatively to protect your roof and the environment. We charge only a nominal fee to have us reapply the inhibitor annually or biannually.

We will provide you with the moss prevention method that you desire. We can install zinc strips, apply bleach, or zinc sulfate. Regardless of which method you choose, we have the knowledge and expertise to completely remove the moss from your roof, and to further prevent it from growing back in the future, giving your roof longer life and keeping your investment looking its best.

Roof Safety

At Contrast Cleaning Services safety is our main concern. While working on your roof we not only utilize fall protection gear when necessary, but we use fall prevention gear as well. We prefer to use rock climbing gear to keep our technicians safe. This enables us to work on even the steepest of roofs. Once thoroughly trained, our technicians become certified in roof safety and advanced rock climbing methods.

roof safety

Are we in your area?

We perform our roof cleaning and moss removal services in Aloha, Beaverton, Canby, Clackamas, Estacada, Forest Grove, Gladstone, Gresham, Happy Valley, Hillsboro, Keizer, Lake Oswego, McMinnville, Milwaukie, Molalla, Newberg, Oregon City, Portland, Salem, Sandy, Sherwood, Tigard, Troutdale, Tualatin, West Linn, Wilsonville, Woodburn, OR.

Give us a call and you will see…

…Our Difference is Clear™

503.266.8985 Licensed, Bonded, and Insured.