The Importance of Roof Cleaning

Moss removal and annual maintenance is crucial to maintaining the life expectancy of your roof.

Living in the Pacific Northwest, moss is no stranger to us! It builds up anywhere, everywhere and on everything.  It not only looks bad, but it can cause quite a bit of damage to your home, especially your roof.

Let’s start with where moss likes to grow.


Moss thrives on moisture and little sunlight so it will grow just about anywhere. You may notice moss growth on parts of your roof that get the most shade particularly in damp, dark and cool areas.  The best way to avoid damage to your roof and further build-up of moss, is annual roof cleaning preventative maintenance.

How does moss damage your shingles?

While moss may have some positive effects in certain environments, your roof is not one of them.  Moss holds moisture and any moisture or standing water on your shingles causes them to deteriorate quicker.

Moss can build-up on top of your shingles, as well as under the shingles and in small cracks.  As the moss continues to grow, it pushes the shingles up, away from the roof deck allowing water to seep in.  If shingles have been lifted or start curling, they can catch the wind and be blown away or torn off.  Excessive water damage can cause mold, rotten plywood and other leaks.

Pressure Washing Shingles

How do you get rid of Moss? Let’s begin with what NOT to do.

Do not pressure wash or scrape moss away from your shingles unless you want the granules to go with it!  Pressure washing or scraping removes the granules on your shingles which are essential to protecting the shingles from sunlight, weather and other environmental hazards.

There are many chemicals out there you can use to remove moss from your roof. Unless it’s specifically designed for your roof, do not use it! We care about your roof which is why we use the eco-friendly Roof Shampoo System that gently washes away moss and algae leaving your roof and your landscape, clean and healthy.

Why you should have your roof cleaned by Mark’s Custom Exteriors:

  • Long-term savings – Avoid extra expenses in an early roof replacement. Maintaining your roof by keeping it clean with annual maintenance keeps your roof life expectancy and may even extend it.
  • Keep your insurance – Insurance companies want to maintain your roof just as much as you do. If they feel excessive dirt or moss build-up may be causing damage, they may cancel your policy.
  • Trained and Certified Professionals – Mark’s has been trained and certified by Roof Shampoo® so you know you’re getting an experienced and knowledgeable professional.
  • Full Assessment of Your Roof – We want to make sure your roof is in tiptop shape! When we provide estimates, we feel it is important to perform a thorough examination of your entire roof’s integrity.

Don’t forget to ask about our gutter installation services! Give Mark’s Custom Exteriors a call at (503) 397-2215 or Fill Out Our Free Roofing Consultation Form.

Angie Holcomb
Author: Angie HolcombIn late 1993, one year after their marriage, Angie and Mark Holcomb decided it was time to follow their dream, and the couple set out to launch their own business. One year later, in 1994, Marks Custom Exteriors was established, one loving couple, one new truck and a passion for their vision. 25 years and many roofs later, MCE has grown to become Portland's premier roofing company and one of the only Nationally Recognized Roofing Companies in the State of Oregon as a GAF Master Elite Contractor. They remain committed to building lasting relationships with their customers through outstanding customer service, expert craftsmanship, and professional behavior and appearance among every member of our team.