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Silent Invasion: Understanding How 5 Common Moss Types May Be Effecting Your Roof

Alaska and its picturesque landscapes are covered with lush and dense greenery. Many people refer to the amazing evergreen forests but a less mentioned one is something you should pay attention to, Moss. 

While Moss does add a certain charm to the scenery, it can damage the integrity of your home’s roof. Alaska’s damp climate has homeowners battling a moss invasion amid their rooftops. Today we are going to delve into the common moss types, their specific impacts, and the best methods to win the war on moss. 



Hypnum Moss

Hypnum moss, also referred to as feather moss, is one of the most common moss varieties found in Alaska. Its dense, carpet-like growth can quickly cover large areas of rooftops, particularly those shaded by overhanging trees or buildings. 

Hypnum moss loves a moist environment, making Alaska's rainy climate ideal for its to spread if unchecked. The moss retains moisture and promotes the growth of algae and other moisture-loving organisms that lead to decay. Making it something you definitely don’t want hanging around on your roof.

 Sphagnum Moss   

Sphagnum moss, often referred to as peat moss, is renowned for its water-retention properties. While it plays a vital role in the formation of peat bogs and wetlands, it can also be problematic when it colonizes roofs. 

Sphagnum moss is prone to water saturation, creating an environment conducive to rot and fungal growth beneath your roofing materials. Another factor is its acidic nature of the moss which accelerates the deterioration of shingles and other roofing components, leading to costly repairs and possible replacements.

  Polytrichum Moss

 Polytrichum moss, commonly known as haircap moss, is characterized by its tall erect stems and dense foliage. Although it typically thrives in moist terrestrial habitats, it can establish itself on roof areas with poor drainage. 

Polytrichum moss can trap debris and organic matter, furthering the issue of moisture retention on rooftops. Its presence can compromise the structural integrity of a roof over time and create unsafe and damaging conditions.

A growth of Ceratodon Moss
Ceratodon Moss

Ceratodon Moss 

Ceratodon moss, also called red-stemmed feather moss, is a species known for its ability to colonize various substrates, including roofs. A rapid growth rate and tolerance to adverse conditions make it a nightmare for homeowners battling a moss infestation.

 Ceratodon moss can cling tightly to roofing materials, making it challenging to remove manually. The strong roots are especially damaging to shingled rooftops, which make it a prime candidate for the Soft Wash roof cleaning method we use. 

 Racomitrium Moss 

 Racomitrium moss, commonly referred to as granite moss, is well-adapted to harsh environmental conditions prevalent in Alaska. It often thrives in rocky or exposed areas but can also colonize roofs, especially in regions with high humidity levels. 

Racomitrium moss forms a dense mat that compromises the drainage system of the roof. Its presence can trap moisture beneath roofing materials, leading to decay and structural damage over time. Depending on the slope of your roof this moss is a must to remove as soon as possible.


Well, we hope learning a brief overview of these different types of Alaskan moss can be effecting your home. 

But that begs the question, what do you do about it?

Here’s 5 Steps to combat your moss infestation

1. Regular Maintenance: 

Implementing a proactive roof maintenance strategy by routinely inspecting for signs of moss growth and promptly addressing any issues while they are small, this can save you tens of thousands of dollars over the lifespan of owning your home.

2. Trimming Overhanging Branches:

 Reducing shade and improving air circulation on the roof by trimming branches that obstruct sunlight and promote moss growth. This can be harmful and unsafe if not done correctly, please consult a professional if any large trees or branches are overhanging your home.

3. Improving Drainage:

Ensure proper drainage by clearing debris from gutters and downspouts and repairing any leaks or drainage issues promptly. We regularly find clogged downspouts and gutters that are damaging homes.

4. Chemical Treatments: 

Consider applying moss-killing products or eco-friendly solutions to inhibit moss growth and prevent future infestations. Many advertised consumer level products are not of proper strength for any significant moss growth, please DYOR on applying chemical treatments on your own.

5. Professional Cleaning: 

Hire experienced professionals to safely and effectively remove moss from the roof using specialized equipment and techniques. Two major factors to consider when selecting professional moss removal, is that pressure washing it away can void the warranty on your roof (More on that here) and that Soft Wash methods are the proven best practice in the industry. If a company is not using Soft Wash methods, it is likely not aware or educated on the best practice to protect your property.

In conclusion, the various types of moss may have very different visual and growth qualities. They do all contribute to degrading the health of one of your biggest investments, yourr roof. 

It is best to stay on top of preventative maintenance, but who are we kidding, with life and sometimes things get away from us. Our roof is usually out of sight and out of mind, so to give yourself peace of mind… Have a professional come evaluate your moss situation and get your home protected.

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