Moss on Your Roof? - Your Ultimate Guide to Moss Control

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Moss on Your Roof? – Your Ultimate Guide to Moss Control

Moss on Your Roof? – Your Ultimate Guide to Moss Control

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Is your roof getting more green moss each day?

Is it only multiplying and growing in your habitat?

Should you take control now or wait for it to do damage and have you buy a new roof?

Keep reading to know about what they are, how they form, and how to eliminate them.

First Things First: What Is Moss?

Moss is a small, unassuming, and not well known as a flowering plant but is just as complex and extremely interesting.

It performs a vital role in the health and function of our environment.

It belongs to a diverse group of Bryophytes, including Liverworts and Hornworts.

Bryophytes are among the simplest of terrestrial plants.

It is one of the earliest plants to become adapted to live on dry land that has developed from algae.

Moss might be small in size, but it is one of the largest groups of land plants and can be found WORLDWIDE in various habitats.

Why Is Moss Growing on Your Roof?

Moss thrives in a cool, moist environment and damp climate. Besides roofs, moss grows on:

  • Trees
  • Rocks
  • Fences
  • Any damp surface


If you find moss on your roof, it’s likely because your roof is shaded by trees or a roof structure, allowing moisture to stay and causing moss to grow.

A non-vascular plant absorbs water through its leaves instead of roots.

Its seeds, called spores, are tiny one-celled reproductive units that form air-borne and find their way onto roofs via wind.

Once the spores get on the rooftop, they merge in the spaces between shingles and burgeon into thick spongy moss.

Since moss thrives in a damp climate, areas of the roof that get the least amount of direct sunlight, like north-facing sections or areas shaded by tree branches, make it an ideal spot for it to sprout.

Once it establishes itself, it soaks up rainwater like a sponge and can spread across the entire roof and grow a few inches thick.

How Does Moss Damage Your Roof Surface

Is it that much of a big deal? Having a little moss can’t be that harmful? WRONG.

A small amount is harmless, but if you choose to ignore it and leave it untreated, it can cause significant damage and degrade the structural cohesion of your roof.

Roof moss begins with a thin dusting of green that you may notice only from low angles.

This thin layer on the top of the roof shingles gradually scales up and becomes wide, thick, and mat-like.

The seams between the roof shingles and the shingles’ edges also grow moss because they tend to be especially shaded.

As it thickens, it starts to work its way under the shingles and raises them to the upper roof.

If you have wood shingles, this process can happen UNEXPECTEDLY because the wood’s porous surface is prime real estate for moss growth.

It Does Not Stop There

Once moss has adhered to wood shingles, it will be more difficult to remove than the relatively smoother planes of composite or asphalt shingles.

Once the moss becomes a thick mat, it becomes a sponge that absorbs and retains all moisture.

This stored water quickly works its way under and between the roof’s shingles and then onto the lower levels of the roofing felt and its structural elements.

This eventually leads to rotting, and rotting leads to decaying of roofing materials.

The precipitating cycle can even destroy a roof in a few months.

At this point, removing moss is crucial to protecting your roof and the rest of the home’s structure.

Before You Begin: Things to Consider on Your Roof Surfaces Before Moss Removal

All it takes is for one spore to land and inhabit your roof for it to develop into moss and spread like wildfire.

When it does, it can come with harmful issues for your home.

Before you proceed to moss removal, consider these things:


When moss grows abundantly, it becomes a heavy blanket on top of your roof because moss absorbs water and moisture and leads to rot, bacteria, and mold growth.

This growth can shorten your roof’s lifespan remarkably.

Roof mold also is an invitation to rodents and critters who feed off the mold and roofing materials.


Moss on roof can also creep underneath your shingles, tiles, and slates, uprooting them from your roof and causing immense damage.

This uprooting can cause holes, leakage, and your roof’s structural degeneration.

When removing moss from your roof, tiles will fall back awkwardly after losing the moss structure that once held it up.

Structural Damage

Most people tend to walk on top of their roof plane to clean or undertake any damages.

However, roofs can’t carry the weight of a human being and can lead to broken tiles or, worse, a major injury.

Unless you’re a trained professional roofer, it’s best to attempt moss removal from the safety of your ladder.

Chemical Consequences

Trying to remove moss from your roof with a household chemical solution can cause more harm than benefits.

Some cleaning products have properties that result in unfavorable outcomes, like lead flashing when it interacts with roofing materials.

This will end up staining both the lead and different parts of the roof.

Instead, hire a professional roofer with exclusive specialist products better suited for roof cleaning.

Ways on Removing Moss

The best way to prevent moss is to kill moss from your roof.

Some methods and materials could help you contain roof moss growth.

Moss-killing products are generally grouped into TWO MAIN TYPES: dry powder and liquid form.

Dry Power Moss Killer

A dry powder moss killer is applied by sprinkling the powder in multiple lines parallel to the roof ridge of the house, with a distance of about 2 to 4 feet apart.

When it rains, the water combines with the powder and runs down toward the eaves.

After about a week, the clough should be dead.

A dry powder killer requires that you go onto the roof and take stock of the moss problem during application.

This allows you to determine the extent of the moss problem and plan the following removal process.

Dry powder killers can be difficult to distribute evenly, and they can leave white streaks that sometimes remain on the roof until several hard rain showers wash them away.

If a strong wind comes along before the rain, dry powder moss killers can blow off before it has a chance to work on the moss.

Liquid Moss Killer

A liquid moss killer comes in a container that attaches to a garden hose and blends in as the water flows.

Liquid moss killers cover the roof more evenly than dry powders, and they let you stay on the ground for the application.

It’s similar to a power washer to remove moss from your roof.

If the garden hose doesn’t reach the roof’s peak from the ground, you can spray while standing on a ladder.

Even if the application can be easier than with dry powders, you will still need to mount the roof later on to remove the dead moss.

There are other products that you can try to remove moss.

Bioadvanced Moss & Algae Killer & Cleaner


This is made from potassium salts of fatty acids and inert ingredients in liquid form.

Unlike zinc-based moss killers, this product is known for being non-corrosive to metal vents and gutters.

The spray nozzle creates a flat stream that is easy to apply.

That way, you prevent moss, remove dead moss, and keep the gutters clean too.

It also keeps the sprayed area moss-free for months afterward.

Moss B Ware


This is a proven moss killer and moss deterrent.

Moss B ware is an on-the-budget and wide availability product.

If you prefer liquid applications, you can mix this dry product with water at the rate of 3 pounds per 5 to 10 gallons of water, which is enough to kill moss over an area of 600 square feet.

Moss Out! From Lilly Miller


If you have moss growing on the north side of your roof, getting rid of the patches on the roof and shingles can be a challenging task.

You can spray the moss killer and get the job done in a short time without any hassle.

This moss remover works slowly but surely.

For the first few days, the effect of the moss remover will appear as if nothing has changed. Eventually, the clough will lose its green color and turn black.

Then within a few months, it will be completely gone.


Most clough killers work at any time of the year, but it is usually applied in the early fall when sunlight diminishes and moss develops.

Moss removal must occur after they are fully dead, which can take a month or two.

How to Remove Moss – Moss Treatment

Here’s how to remove moss from rooftops with these easy instructions.

But first, let’s take a look at what you’ll need:

  • Safety goggles
  • Rubber gloves
  • Safety rope
  • Work clothes
  • Ladder
  • Hard Hat
  • Safety Harness
  • Garden hose equipped with a spray nozzle
  • Moss-remover of choice
  • Large spray bottle
  • Scrub brush
  • Long-handled soft-bristle brush
  • Power washer (OPTIONAL)


Step 1: Prepare

You must ALWAYS dress appropriately no matter which technique you end up doing. Wear work clothes, safety goggles, rubber gloves, a cap, and roofing shoes.

Have a safety rope if you’re going to the roof’s ridge. Cover nearby plantings with plastic sheeting.

Set a ladder securely, grab the hose, and start climbing.

Be extra careful if you plan to do it on a wet roof.

Step 2: Water Spray the Roof

Spray all moss-covered roof areas with water.

Do not use chlorine bleach, even if your agenda is just for roof cleaning.

Always work from the top of the roof then down to ensure water pours off the roof so the water or tools won’t lift and damage shingles and tiles.

Step 3: Scrub Shingles

This is OPTIONAL, but use a long-handled soft-bristle brush to gently scrape or pluck moss from roof shingles or tiles.

Work on one small section at a time to better control the brush and your scrubbing motions.

Step 4: Apply Moss Remover

There’s no need for a chemical solution.

Soak the moss and let the solution set per the manufacturer’s instructions.

But if you decide to use a homemade moss remover, let it sit on the roof for about 20 minutes.

Step 5: Rinse Roof

Grab the hose, climb the ladder, and rinse off the moss-remover solution and now-dead moss.

Remove the remaining residue with a scrub brush, and rinse the roof again.

Step 6: Power Washer (Optional)

This step is totally NOT REQUIRED, but you can use a power washer to clean moss (NOTE: Make sure your shingle roof and roof itself have to be completely fine and undamaged.).

Also, when using this, you will need to stand on the roof above the mold to point the power washer DOWNWARDS for proper drainage.

If you opt for a power washer to remove the roof moss, use it on the lowest pressure setting possible.

How to Prevent Moss: Do’s

We can’t just remove clough but not prevent them from growing again. You can do these preventive measures to completely escape from this problem.

  • 1 – Seek help from Mr. Sun: You can start by letting sunlight exposure in! Trim the branches that hover on your roof that make moss grow.


  • 2 – Weekly or monthly routine of roof cleaning: Laundry detergent and dish soap will not help maintain the overall health of your roof. Since laundry detergent is a no-go, try a different cleaning solution.


  • 3 – Installing zinc strips: You can nail them along the lower roof. This inhibits clough from growing.


How to Prevent Moss: Don’ts

We showed you some tips you can use to stop moss growth, but we also have to warn you about certain procedures you MUST avoid AT ALL TIMES to prevent any roof damage from happening.

  • 1 – No to pressure washers: Never use a pressure washer or a pressurized stream of water on your roof. A pressure washer is strong enough to break a shingle’s adhesive and lift it up. Pressure washing can result in needing a new roof or roof replacement.


  • 2 – No to a leaf blower: You can’t shoo away clough with a leaf blower like most plants. Other plants do not stick and expand, unlike clough.



So, is moss bad for your roof?

Yes, 100%!

Even if it starts small, it will definitely expand and create despicable damage.

It’s best to know now, to avoid the need for roof replacement.

If you ignore it and let it grow for a few months, your family will just be surprised that you need a new roof!

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