Tuesday, August 16, 2022
HomeFactsWhy Does Moss Grow On Roofs

Why Does Moss Grow On Roofs

Will A Tree Die If Its Covered In Moss

How To Remove Roof Moss – And Keep It Away

Moss is fairly common on tree trunks and can develop when the trunk becomes wet and moss spores are present where water seeping down from above feeding the moss.

Moss appears as light green sheets over clumps around trees which means theyre getting plenty of moisture. If it is growing on the tree trunk, then there may be moisture around.

However, It does not mean that a forest with moss-covered trees will die but in some cases, moss will continue to grow even if the tree roots are rotting out.

So to some people, this may look like the tree is dying because of the moss when in fact its not due to the moss at all

How To Clean Off Mossy Or Lichens

Do not try to clean a roof like the one shown in this photograph. The shingles are worn out and fragile. It will be impossible to clean the roof without damaging it. A new roof is needed.

In our opinion, any roof surface brushing or raking should be done with great care to minimize damage to the shingles themselves. If there is any doubt about the condition of the shingles underneath the moss, work gently by hand on a small area first to see the condition of the shingles below.

If the roof shingles are fragile, brittle, cracking, curled, the risk of serious damage to the roof during moss removal is much more likely. The roof may look cleaner, but its remaining life may be reduced by aggressive cleaning.

Power washing or brushing: it is possible to remove moss from a roof surface by gentle cleaning using a soft brush or a power washer.

But be careful: power washing or even brushing or sweeping an asphalt shingle roof is itself a process that can damage the roof by breaking shingles or by loosening the protective mineral granules from the shingle surface.

As stated at ASBESTOS ROOFING / SIDING POWER WASHING we do not recommend power-washing asphalt shingles nor asbestos-cement roof shingles nor any other roofing product that can be damaged by high pressure spraying.

Otherwise the debris will wash down and clog roof gutters

How To Treat Moss On Roof Shingles Or Tiles

Moss or algae growth is easily treatable with zinc or copper strips. For their inexpensive price and low environmental impact, copper strips are the most effective and cheapest way to do this. Copper is the third most recycled metal in the world, after iron and aluminium.

Add a 2-inch thick strip of copper across the ridge of your roof, as close to the pitch as possible. This will protect roof shingles and tiles from growing moss. If your roof is larger than average, you might need to fix more than one strip. In this case, add a copper strip at the midway point down the roof, too. When it rains, the copper salt will be washed down the roof from the strips youve fitted and will coat the roof. This then prevents moss and algae from growing.

If you need help or advice, call our friendly team of advisers on 01752 692 760. You can also use the live chat function in the bottom right-hand corner of our website.

Recommended Reading: Rv Rubber Roof Repair Kit

Beware Of Diy Roof Cleaning

If you decide to remove the moss on your roof yourself, think about the dangers of working at height, on your roof. Working at height without the correct training, experience and equipment can lead to serious injuries, or death. Also, cleaning in a way that is not bets for the roof can lead to damage and costly repair bills.

Leeksons Exterior Cleaning offer roof cleaning services throughout South Wales and the South West. With over 20 years experience we have cleaned many roofs. Most of the time we are able to clean your roof without setting foot on it. By using out specialists tools we are able to scrape the moss growth from a mobile scaffold tower. This means a safe working platform for our operatives. We also have safe ways of applying biocides that will prevent the regrowth of mosses. If you have been searching for roof moss removal near me then get in touch with us to arrange your free quotation.

Our Services

What If The Moss Grows Back

Why is moss growing on my roof and how do I stop it ...

If the moss does return, do not rely on harsh chemical treatments or dry spells to kill it. Chemical treatments may harm shingles as well as moss, creating a more significant problem. Dead moss must still be removed by hand, or it will impede the flow of water off the roof and create issues. It may cause standing water. It may also clog gutters or allow for leaks.

You May Like: How Much Do New Shingles Cost

What Are The Effects Of Moss Growth On Roofs

Because moss or lichens growing on a roof surface will hold moisture on the roof longer than other areas, these growths can reduce the life of the roof covering.

Particularly where the roofing materials are asphalt shingles or wood shingles, holding water on the roof surface by any means speeds up wear on these shingles. In freezing climates there may be faster frost damage, cracking, and wear of the shingles under the moss or lichens.

Even in non-freezing climates, the roots or growth structures of moss or lichens eventually penetrate and separate the roof shingle materials, speeding their demise.

How Moss Damages Shingles

Moss damages your shingles in three significant ways.

First, moss will strip away the protective oils on your shingles, making them susceptible to erosion and sun damage. Without any protection, your shingles will warp and crack in the sun, significantly shortening their lifespan.

Second, moss absorbs water. So every time it rains, the moss sucks up more moisture and spreads farther across your shingles, eating away at this outer protective layer. If ignored, this moisture buildup will ruin your shingles, and you will eventually need to replace your roof.

Finally, moss spreads beneath your shingles. This moss absorbs water and thus allows moisture to invade into the interior of your home. When moisture builds up on the inside of your home, it leads to wood rot. This is the worst case scenario because it can mean far more extensive repairs to your home.

Recommended Reading: How To Repair A Trailer Roof

How Do I Get Rid Of Moss On My Roof Without Chemicals

To follow up on the previous section, there are some other strong substances that you can use, which are not considered artificial. For example, you can get rid of moss using a mixture of water and either Dawn Ultra dish soap or chlorine bleach. Again, though, you can easily substitute these products with white distilled vinegar.

What Causes Moss Growth


Shaded areas exposed to frequent damp, cool weather will quickly encourage moss to grow on your roof. The presence or absence of sunlight dictates the amount of moss or algae growth.

Moss absorbs and retains water. If you remove moss from the roof, then you will reduce the possibility of tiles suffering from winter cracks. Furthermore, moss likes to grow on cement and can agitate the bond between ridge/apex tiles and your roof.

Moss alone cannot damage the tiles. However, the greatest benefit of moss removal is on the gutters. Once moss is removed, there are less blockages and your gutters work more efficiently. Mostly, your gutters require less maintenance. When you reduce the chance of costly blockages, your gutter guards and down spout pipes will work properly.

You May Like: Extending Roof Overhang

Why Does Moss Grow On Roof Shingles & Is It Bad

We associate picturesque cottages with moss-lined roofs as being dream-like and straight out of a fairytale. But in reality, this green build-up has more of a nightmarish quality to it. Letting moss grow freely across your shingles can put your home, building, or other structure at risk. In this article, we will discuss how moss develops on your roof, why its harmful, and how to get rid of it.

Three Types Of Roof Moss

While there are many different species of moss, there are three prevailing types of moss that often slowly encroach on homes. Over the course of thirty-four years, the professionals here at Roof Life of Oregon have been able to distinguish these three types of green troublemakers.

Roly-Poly Moss

A type of moss that grows underneath the shingles and begins to lift them off their mastic strip. They tend to grow at the ends of asphalt, shakes and tile shingle roofs. It is bright green in color and can appear to glow at times.

Spindly Moss

A moss that is harder to spot. Tends to become rooted in the shingle and eat away at it. This type of moss can disintegrate a shingle if left untreated.

Furry Moss

Mostly seen on wood roofs and occasionally on a tile roof. A distinct characteristic is that it usually grows leaves along with it. This moss is different as it is growing on rotting wood, meaning your roof has wet rot.

Don’t Miss: Add Overhang To Side Of House

How To Treat Moss

Online you can find many suggestions on how to treat moss on your own. While it may sound easy, some of these suggestions are ill-advised and are merely temporary solutions that can lead to a bigger problem.

Despite what those articles say, do not use a pressure washer on your roof! Pressure washing is a surefire way to damage your roofs tiles and shingles. As well, its costly and only removes the surface layer of moss, leaving behind spores that will ultimately grow back.

Other recommendations include hand-scraping moss off your roof, yet hand-scraping is only a preliminary method in the many steps involved in removing moss. Similar to the pressure washer, hand-scraping will only remove the visible layer of moss and fails to get rid of spores and clusters that can spread and stimulate regrowth.

Bleach can also kill moss, but if not used properly, it can lead to discoloration and ruin vegetation on and around your house. Its important to be cautious when using bleach, especially if youre not familiar with the solution as it can irritate the eyes and/or burn your skin. Its often best to leave the chemicals to moss removal professionals like Clean Break Home Services, who use a 12.5% industrial standard bleach solution and know-how to create a safe mixture that offers maximum effectiveness.

S To Take To Keep Moss From Growing On Your Roof

How to Remove Moss From the Roof of Your Home

Moss growth can be unsightly and damaging to your roof moss causes water to get backed-up on your roof, which can lead to water damage. If you see moss growing on roofs in the neighborhood or on your roof, you can take proactive steps to prevent further growth.

1. Always Trim Nearby Trees

When tree branches grow over your roof, they provide shade for your home, which can help keep the temperature cool. However, all that shade also helps create a perfect environment for moss to thrive and grow. Moss needs a shady and moist environment to grow, and overhanging trees create this environment. Trim back the branches on any trees near your roof. You dont have to cut down the trees that provide your home with shade you just need to make sure their branches dont grow over your roof. A professional tree cutter can help you with this task.

2. Clean Your Gutters on a Regular Basis
3. Keep Debris off Your Roof

When debris, like large branches, build up on your roof, the debris can cause water to build up as well. Water, along with shade, are the two elements necessary for moss to grow. If you ever spot a big branch or other debris sitting on your roof, remove the debris right away.

4. Install Metal Strips
5. Install Algae-Resistant Shingles

Recommended Reading: What Size Nails For 7 16 Osb Wall Sheathing

How To Prevent Algae And Moss On Roof Shingles

Moss and algae growth can be prevented, regardless of your roofing system or climate. Homeowners who take steps to prevent moss and algae growth can protect their home’s structure for years to come.

Algae and moss growth on your roof is not only unsightly but can be dangerous to your residential roofing system. Learning how to distinguish between moss and algae, and how to prevent both types of growths will keep your roof protected. If you are struggling with moss or algae on your roof, call a residential roofing professional who can evaluate your roof, and provide the best solution for long-term prevention.

At Pickard Roofing, we think Design. Craft. Renew. We are experienced in all types of roofing systems- and provide the right roofing design and selective craftsmanship for renewing our customers assets. We invite sustainable building customers to give us a call for your free evaluation. For over 90 years Pickard Roofing Company has installed countless metal, tile, slate, TPO, EPDM, and all types of shingle roofing in the Triangle. Our services include residential, commercial, custom architectural metal fabrication, and historical renovation.

Metal Flashings Can Retard Moss & Lichens Growth On Roofs

We have observed that the chemical or mineral salt wash-off from some building materials like aluminum flashing and copper flashing and even some paints which appear to kill of moss, lichens, algae, and fungus, as their extracts are washed over the roof surface. It’s particularly easy to spot this effect by noticing where there are moss-free areas on an otherwise mossy roof surface.

One of our most obvious photos of rain wash off of copper flashing keeping moss off of a roof happens to be on a wood shingle roof, But we see this effect below copper flashing on asphalt shingle roofs as well.

Notice the clear area below the turret on top of this wood-shingled pyramid shaped roof located in Key West Florida.

Chemicals from the metal cap atop the turret and from flashing at the turret base appear to be washing down the wood shingles in a path which prevents or even kills off moss, algae, and lichens on this roof

Installing copper or other metal strips along the ridge of an existing roof will slowly kill off moss or lichens as rainwater washes over the metal and down the roof surface. This method is suitable for both prevention of future or further moss or lichens growth on the roof and for gently treating an otherwise fragile old roof.

Here is another photograph demonstrating the effect of copper flashing on algae, moss or lichens on a roof.


Trim back trees too close to the building: see our tree trimming advice

Read Also: Shed Eave Overhang

Is Moss Bad For Your Roof

There’s much to debate when it comes to discussing the pros and cons of letting moss grow freely on your roof. Some underestimate the impact of moss growth on their homes, while others worry it’ll cause irreparable damage. While it’s widely speculated, we’re here to debunk any myths around roof moss, once and for all.

The Benefits Of Removing Moss

Do you have Moss on your Roof?

While you may not necessarily have to remove the moss-covered shingles before a new roof installation, you should consider it. There are many benefits of removing the moss-covered shingles, including:

  • Reduce long-term costs: By removing the old roof, you keep the opportunity to double-up roof layers during your next roof replacement. The maximum layers of shingles allowed to be on the roof, according to most building codes, are two. So, once you use this strategy, you must tear off both roof surfaces during your next roof replacement.
  • Maintain home value: Are you planning on selling your home soon? A properly replaced roof is more likely to appeal to potential buyers, while a poorly replaced roof may negatively affect your home value.
  • Avoid the risk of damage: You can avoid all of the risks listed earlier in this article by simply removing all of the moss-covered shingles.

Don’t Miss: Large Overhang Roof

Extend The Life Of Your Roof

Now that youve learned how to safely remove moss from your roof, you may be looking for more tips for maintaining your roof.

Roof Maxx roof rejuvenation instantly adds 5 years to the life of your asphalt shingles with just one treatment. Contact us or fill out our free quote form below to learn more about our all-natural treatment today.

What Does Moss Growing On A Roof Mean

Why Does Moss Grow on My Roof? Moss, algae and lichen grow on your roof through a combination of two things: moisture and organic debris. The more water and the more debris, the greater the chance of moss growth. … A well-shaded roof prevents the evaporation of moisture, creating excellent conditions for moss to thrive.

Don’t Miss: Cost Of New Roof California

Want To Get Rid Of Moss

No matter the material of your roofing, effectively washing away these green blotches from your shingles requires a cleaning solution. For heavy-duty cleaning on durable shingles such as asphalt and fiberglass, opt for a solution with industrial-grade chemicals. Combine the solution with a low-pressure power wash to get your roof moss-free.

What Causes Moss To Grow On A Roof

Should You Be Worried About Moss Growing on Your Roof?

Moss spreads via releasing spores like many plants. Moss growth is far more likely on damp, cool surfaces that dont receive much sunlight. This makes north-facing tiled roofs especially prone to moss and algae build-up, as they can quickly take root in the dark nooks and crannies between and under roof tiles, shingles or slates. Roof tiles made from clay or concrete are particularly susceptible to moss growth. This is because their porous surfaces and frequent exposure to rain and damp conditions make them the perfect environment for moss to root down and spread very effectively.

Don’t Miss: How Much Roof Overhang On Shed


Most Popular