Why Moss is Growing on Your Roof and Steps You Should Take ASAP

Moss growing on roofs is a common issue, especially in some areas where the environment is so favorable to moss. Yet it’s a problem that many homeowners will overlook until it becomes a glaring problem. The first time I remember seeing a moss problem on a roof was on a home during a leisurely walk in my neighborhood. I was looking at the architecture of a charming old house and was taken aback to see a thick layer of green moss covering the shingles with black streaks streaming down the roof surface.

why is moss growing on my roof

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I quickly realized the potential damage this moss could be causing and how much it was going to shorten the lifespan of the roof. This unexpected encounter was a wake-up call, prompting me to inspect the roof of my own home, which, to my surprise, had signs of problems.

Why Does Moss Grow on Roofs?

The biggest reason moss grows on a rooftop is environment. Conditions such as shade and moisture in an area can mean that moss will be more of a problem.

One environmental condition that moss loves is shade as direct sunlight can be detrimental to its growth. Tree canopies that are situated on the north side of a home, where sunlight is more scarce, are particularly a problem when it comes to preventing moss on your roof.

Moss also requires a significant amount of moisture to grow and that moisture can also cause a problem for your roof. Roofing materials that have moisture present for extended periods of time can start to breakdown and fail prematurely.

ConditionIdeal Scenario for Moss Growth
Light ExposureMostly shaded areas, especially the north side
MoistureHigh levels of moisture and areas with frequent rain
Roof MaterialPorous materials that retain moisture
DrainagePoor drainage systems that allow water to pool
Air FlowLimited air flow that keeps areas damp
TemperatureCool to moderate temperatures

The parts of my own roof that had moss problems provided the perfect blend of shade and moisture, compounded by the aging roof material on my home, made it clear why the moss was there.

The Risks Involved with Ignoring Moss

Once you’ve seen moss on your roof it’s best to take care of it quickly. Ignoring the problem can lead to significant structural and aesthetic damage. Much like turning a blind eye to a minor leak that gradually worsens into a substantial, costly issue on your roof.

Moss acts like a sponge, retaining moisture against the roof surface which is the biggest problem. This persistent dampness can cause the roofing materials, especially wood shingles, to rot or degrade faster than they normally would. The roofing materials will also start to discolor after a short period of continued moisture on them.

And, over time, moisture can seep beneath the shingles, compromising the roof’s integrity and leading to potential leaks within the home.

When moss begins to grow and take root on the roof, it can cause shingles to lift and shift around. This shifting leads to the deterioration of the roof’s protective outer layer, increasing its vulnerability to wind damage and leaks. The root-like structures, known as rhizoids, of the moss are often the cause of this issue.

Preventing Moss on your Roof

One of the most effective ways to reduce moss on the roof is to reduce the conditions moss thrives under. You can do this by trimming back tree branches that overhang your roof and allow more sunlight to reach your roof.

Making sure your roof has proper drainage is another crucial step to prevent moss on your roof. Keeping gutters clean and free of blockages allows water to flow off the roof. Also look for areas on the roof which may have debris buildup which can block drainage of the roof such as in valleys on the roof.

The best way to prevent moss on your roof is to check your roof regularly. Every month of so take five minutes and walk around your home and look for problems on your roof. Catching these small problems early to can help to prevent damages later.

During these roof check-ups, you can look for early moss growth signs and if needed, clear away any debris that may be collected on the roof. Remember, dealing with moss early on can save you from more intensive and costly repairs later.

Take the DIY Route or Hire a Professional Roofer

While it may seem like moss on a roof is a huge problem many people decide to tackle this problem themselves. And if you can safely go onto your roof and there are some solutions you can use to clean your own roof.

Mixing 1 part vinegar and 1 part water is a great cleaning solution that many people use around the home and it can also be used to clean your roof. Since vinegar is acidic it’s important to test on a inconspicuous area on your roof first.

You can also use a concentrated roof cleaner that is designed to kill moss on the roof. Here are a few that are available on Amazon:

Using a garden sprayer you can apply the cleaning liquid to the roof. If you’re using a commercial product you’ll want to read the instructions and if you’re using the vinegar and water mixture, spray on the roof and let it set for a few minutes.

You can also take a soft bristle brush to help scrub away some of the moss and debris. But only apply enough pressure to take off the moss. The more you scrub on asphalt shingles the more of the granules you’ll scrub off the shingles which can be a problem.

Sometimes, when the moss has gotten really bad it may be time to throw in the towel and call on a professional to clean the roof. If you can catch the moss early enough, a DIY solution may be enough but in more severe cases, to save time and money, hiring a professional may be the best answer.

So, Once the Roof is Clean and Moss Free, How to Keep it That Way

Routine roof maintenance and inspections are imperative to prevent moss regrowth. In order to prevent moss from attacking your roof again, here are some maintenance practices that should become part of your regular roof routine:

  1. Inspect the roof regularly: Schedule bi-annual inspections of your roof with a professional roofer, ideally during the spring and fall. Many local roofers will offer this service for free or with a low cost. It’s also important that you take a look at your roof from the ground level every month or so to identify problems early.
  2. Clean Your Gutters: Keeping your gutters clean to prevent blockages that can lead to water pooling. Proper water flow off the roof is crucial to keeping the surface dry and inhospitable to moss. It can also help to prevent roof ice dams in winter.
  3. Trim Overhanging Branches: Moss thrives in shade so remove that tree canopy you have over the home. This not only reduces shade on the roof, which moss loves, but also minimizes the accumulation of organic debris that can fall on the roof.
  4. Moss Prevention Treatments: Consider applying a moss preventative treatment as part of your routine maintenance. There are several environmentally friendly options that won’t harm your plants or pollute runoff water available on Amazon.
  5. Don’t Let Debris Buildup on Your Roof: Regularly remove leaves, twigs, and any other debris from your roof that collects in areas such as valleys.

It may seem like a chore, but it’s a critical step in preserving the health and functionality of your home’s roof and only takes few minutes each month to do.

Parting Thought

Taking care of your roof isn’t just about dealing with moss. It’s about protecting your home from the top down. A well-maintained roof shields your home from the elements, maintains its structural integrity, and contributes to your property’s overall aesthetic and value. Considering the roof as a critical component of your home’s health encourages us to undertake regular maintenance, not as a burdensome task, but as a necessary and rewarding effort to safeguard our homes. It’s a reminder that every part of our home needs care and that preventive steps today can avert major repairs tomorrow. In this way, addressing something as seemingly simple as moss can underscore the importance of holistic home maintenance.

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