Our roofers are insured by a $5 million dollar general liability insurance. Fully compliant & in good standing with WBC.

How Does Moss or Algae Kill Your Roof?

Have you ever noticed that green or brown growth on your roof? Moss or algae, these organisms not only affect the aesthetics of your home but can also pose a significant threat to the durability and longevity of your roof. In this article, we will delve into the world of moss and algae, understand how they damage your roof, and learn how to keep them at bay.

Understanding Moss and Algae Growth on Your Roof

Moss and algae are common organisms that may find a home on your roof, especially in Vancouver’s weather. They thrive in wet and humid conditions and can lead to significant roofing issues if left unaddressed.

Conditions Favoring Moss and Algae Growth

If your home is situated in a rainy, humid area, or receives a significant amount of shade, then chances are you might be dealing with moss or algae on your roof. These organisms require a specific set of conditions to grow, which include warm to cool air, moisture, and protection from direct sunlight, similar to how extremes of hot and cold can shorten a roof’s lifespan.

Distinguishing Between Moss and Algae

Identifying whether you have moss or algae on your roof is one of the first steps towards solving this problem. Moss is a plant that tends to form small mounds on the roof and can accumulate into rounded tufts over time. It is typically green during the wet seasons but can turn greenish-brown during the drier periods.

Photo Credit: Pixabay

On the other hand, algae, which is not a plant but an organism spread by spores, grows flush against the shingles and fixtures on your roof. It can be brown, gray, blue, or green and appears on the shingles in streaks that run down the roof pitch vertically.

Photo Credit: Wikipedia

The Impact of Moss and Algae on Your Roof

While moss and algae might seem harmless at first glance, they’re actually among the common threats that can impact your roof’s structural integrity over time.

Algae: An Underestimated Threat

Algae growth can affect the roof’s ability to reflect sunlight, which, similar to locating a roof leak, can be challenging but crucial because it could potentially increase your heating or cooling bills.

Moss: The Silent Destroyer

Moss can cause significant damage to shingles, particularly asphalt and wood shake shingles. Shingles are designed to lie flat against the roof to promote proper drainage. However, moss, over time, can grow up the pitch of the roof, causing the shingles to lift or curl. This eventually leads to water intrusion, moisture damage, wood rot, and even roof leaks.

Preventive Measures Against Moss and Algae

There are several preventive measures you can take to protect your roof from moss and algae growth, which form part of the best ways to proactively protect your roof overall.

Trimming Overhanging Trees

Overhanging trees can block sunlight from reaching your roof and trap moisture from heavy rainfall, creating the perfect environment for moss and algae growth. Trimming back branches that extend near or above your roof will allow more sunlight to hit your roof and keep it drier, reducing the conditions that these organisms need to grow.

Regular Removal of Debris

Regularly removing debris from shingles and gutters, especially after a storm, is another way to prevent moss and algae from growing. Debris like leaves, twigs, and pine needles can trap water against the roof, creating the ideal environment for moss and algae. By keeping roofs and gutters clear of debris, you can prevent these organisms from getting a foothold on your shingles.

Professional Roof Cleaning

Professional roof cleaning companies have the knowledge and experience to clean your roof in the safest and most effective ways, similar to how they protect your property during a repair job. Improper cleaning can cause granule loss on shingles or other damage, resulting in roof leaks or worse. Therefore, DIY roof cleaning is generally not recommended. Instead, trust the professionals to do this job for you.

Choosing Copper-Infused Asphalt Shingles

If your shingles are damaged, consider a different type of replacement shingle. Copper-infused shingles prevent moss and algae from growing. Some companies even use zinc in combination with copper to prevent these types of growths. Installing copper-infused asphalt shingles on your home will ensure that you’ll never have to worry about moss or algae again.


Moss and algae might seem like harmless growths on your roof, but their presence can lead to significant damage over time, affecting the durability and longevity of your roof. Understanding their growth conditions, identifying the type of growth on your roof, and taking preventive measures can help protect your roof from their damaging effects.

Remember, a little preventive maintenance goes a long way in maintaining the health and extending the lifespan of your roof, which you can understand better by exploring the expected lifespan of a new roof.

Roof’s Damaged Already? Worry Not.

If your roof has already fallen victim to moss and algae growth, it’s crucial to take action promptly. Don’t let the damage worsen and compromise the integrity of your home. Our team of roofing experts is here to help you restore and repair your roof in a timely and efficient manner.

Visit our city pages to find professional roofing services

Our experienced professionals will assess the damage, provide reliable solutions, and restore your roof to its former glory.

Table of Contents