Roof leak? Call us.(503) 925-0125

How To Get Rid of Green Gutter Slime on Your Roof

Posted March 20, 2024 by Daniel White
Let Us Help

Key Takeaways

  • Green slime is a nasty, slimy build-up of moisture, algae, and moss in your gutters that can lead to issues with your roof.
  • Causes of green slime include the presence of algae, moisture stuck on the roof, a lack of sunlight, and incorrect gutter installation.
  • Gutters are not always as necessary as homeowners think. Often, all you need to direct water is a downspout, and it can make a significant difference in preventing slime buildup.
  • To treat green gutter slime on your roof, it’s best to seek an inspection from a professional service that can identify the severity of the issue and the best solution.

Green gutter slime is notorious in the Pacific Northwest. It’s not caused by your roof or anything you’re doing wrong. Unfortunately, it’s often actually created by your gutter system and how your roof was put together.

Although a gutter system is often seen as a necessity for homes in wet areas, a downspout is often all you need. This guide covers the key things you should know about green gutters and downspouts and how to manage them.


What Is Gutter Slime?

Gutter slime is a wet, slimy build-up of algae and moss in your gutters that gets stuck and doesn’t wash away. This build-up can collect dirt and debris and trap water in your gutters, preventing them from draining properly.

Over time, this gutter slime only gets worse and can disrupt your entire gutter system. In severe cases, this gutter slime can trap moisture on your roof and lead to additional issues like leaks and breakdown of your shingles.


Causes of Green Gutter Slime

Green gutter slime is an all-too-common sight on Portland roofs. Between the wet conditions of Portland and the prevalence of different types of moss and algae, green gutter slime is almost expected to grow after enough time. It is a difficult problem to get in front of because of how stubborn it is, but recognizing the following causes can help.


The Presence of Algae, Moss, or Mold

Algae, moss, and mold spread through spores and by reproducing. If these organisms are around already, then they can spread to your gutters or roof. Because your gutters and roof often have moisture on them, they create the perfect environment for the surrounding spores to latch on and start growing a carpet of roof moss.


Moisture Retention on the Roof

Moisture is an essential piece of the formula for algae and moss growth. If your roof retains moisture or has poor drainage in the gutters, green slime may arise. Recognizing areas of moisture retention on your roof is crucial for preventing an environment where these organisms can grow and thrive.


A Lack of Sunlight and Ventilation

A lack of sunlight and ventilation goes hand in hand with moisture retention. If the roof does not have a chance to dry out, it will only encourage the growth of algae or moss. These conditions are common if your roof is shaded by trees or your gutters are blocked by leaves and debris that prevent airflow—in these cases, the growth of gutter slime is very likely.


Incorrect Gutter Installation

Incorrect gutter installation is one of the most common issues leading to green gutter slime—less experienced services will put gutters in places where they aren’t necessary. When it’s time to install gutters on your new home, these gutter guys install them in places where they don’t need to.

It’s not because they are trying to get more money, they just think that everywhere water drips require a gutter—this isn’t the case.

These gutter guys will put gutters on the dormer, and rather than connect it to the lower gutters with a downspout, they’ll cut the backsides and allow the water to run down the roof where it would’ve dripped anyway. The gutters weren’t even necessary to get this same effect, and now you have water constantly running down your roof.

Assessing the Severity

Many homes in the Pacific Northwest experience at least some green slime buildup due to the moist and rainy conditions. Typically, a little slime is harmless. However, if the issue goes unaddressed, then it can compound into a more problematic issue.

The best way to assess the severity of the issue is to have a professional roof inspection service come to assess the issue.

If you ignore the issue, then it can become worse over time, leading to some of the following issues:

  • Clogged gutters and improper drainage
  • Pooling of water that can lead to leaks
  • Wear and tear to your roof fascia
  • Runoff over your gutters and risks to the foundation
  • Premature wear of roof shingles


How To Prevent Green Slime from Forming

When it comes to roofing, the best repair is always prevention. Keeping green slime on your roof can be tricky, but there are steps you can take to minimize the risk and prevent the conditions that cause green slime buildup.

Utilize the following strategies to prevent green slime from forming:

  • Clean your gutters – Dirt and debris in your gutters trap moisture in your gutters, so a regular gutter cleaning minimizes the risk of creating a good environment that allows for slime growth.
  • Perform regular roof inspections/maintenance – Regular roof inspections and maintenance will ensure safe water runoff, prevent water buildup, and allow for moss removal before it becomes too significant.
  • Trim any overhanging tree branches – Overhanging tree branches can block sunlight and drop organic matter on your roof, so maintenance helps prevent an ideal environment for slime growth.
  • Improve roof ventilation – Improving roof ventilation makes it less likely to retain moisture and eliminates the conditions for slime growth.
  • Monitor where water is running off of the roof – If you notice that water is running off the roof slowly or remaining in a single location, you should contact a roofing company to address it.

However, even with rigid preventative measures, gutter slime can be too difficult to prevent. In these cases, you should look into treatment options.


How To Treat Green Gutter Slime

Despite how frustrating it is to prevent, if green gutter slime does start to appear on your roof, you can take steps to treat it. With the help of a professional service, you can tackle the annoying green gutter slime with ease.

At Roof Life of Oregon, we take steps to both treat gutter slime and address the root causes. Some of the strategies we’ll use to help you address green gutter slime include:

  • Cleaning your gutters – If green slime has built up in your gutters, then a gutter cleaning with the right chemical solution and tools will help clear out the slime and other debris in your gutters, especially since the slime rarely washes away on its own.
  • Perform moss removal – Using a mix of a chemical solution treatment and physical moss removal methods, we’ll remove moss and take steps to prevent it from spreading further along your roof and gutters.
  • Remove your gutters from the dormer – If you’re re-roofing, we’ll likely coach you to remove the gutters completely off your dormer. If it’s a low enough dormer and the water’s not dripping that far, we might put a nice fascia board up there, have it painted, and let the water drip since it’s running there anyway.
  • Capping off the gutters – If it’s a roof that can be maintained, we can refer you to one of the local gutter companies we love who can correct the issue by capping off the end of the gutters. They’ll put some downspouts down the side of your dormers, lead them into the gutter, and stop that dripping on your roof.

In any of these cases, it’s best to leave the treatment process in the hands of a professional roof maintenance service. The right service will inspect your roof to understand the scope of the issue and determine the best possible solution based on your roof.


Prevent Green Gutter Slime with Regular Roof Maintenance

Green gutter slime is a nuisance for home and business owners, and too much buildup will only result in problems like clogged gutters, a risk for leaks, and damage to roof shingles. Fortunately, the right professional support will help you keep green gutter slime on your roof to a minimum.

Roof Life of Oregon can respond to your home to help you address any issues with your roofing system. Whether you have clogged gutters or are in need of professional moss removal, we’ll respond to keep your roof system in its best shape and prolong the life of your roof. We support clients throughout Oregon with everything from periodic roof inspections to full-on roof replacements.

Don’t settle for green slime on your beautiful roof. Call Roof Life of Oregon and let us diagnose your problem with a free inspection.

Previous Article
Next Article

Call Roof Life of Oregon Today

If you’re looking for a team that is as knowledgeable as they are kind and proactive, Roof Life of Oregon is the choice for you. Contact us today to experience the difference for yourself.

We’re Here to Help You

A healthy and properly functioning roof, free of moss and debris is also appealing and a source of homeowner pride.

Get a free quote for an inspection today.