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How To Clean Mold From Roof Shingles

Get A Sprayer And Mix Solution

How to Clean Your Roof with Jomax Roof Cleaner

A garden sprayer with a pump-action handle works well to apply the vinegar solution. A tall ladder will allow you to spray the entirety of the roof from the ladder without walking on the roof. If you need to get on the roof, you should use the appropriate fall arrest safety procedures and walk carefully.

To mix the bleach solution, simply dump your vinegar into the garden sprayer with about an ounce of dish soap.

How To Clean Mold Off Roof Shingles

  • Written by Carol S. on Dec 13, 2009To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.Reviewed by

Mold stains can form on roof shingles that are in permanent shade. These stains will discolor your roof and damage the shingles over a period of time if left alone. Extensive mold growth can also expose the interior of your attic or crawlspace to mold spores, carrying the problem over to the inside. Not to worry, though, because you can clean the mold off with basic household bleach and save your roof long before you need an expensive replacement. Follow the steps below to remedy this problem.

Protect Your Plants and Lawn

Splash the plants and parts of your lawn that are close to the sides of your house with water to protect them from the bleach solution. You can also cover them with tarps or plastic sheeting, which will protect the soil around your plants as well. Make sure that you create a wide radius around your home to be safe.

Make and Apply the Bleach Solution

Check for Cleanliness and Rinse

Allow the solution to soak into the shingles for at least 15 minutes. If they are severely molded, you may want to give it a little longer. Next, rinse the shingles thoroughly with a garden hose at low pressure. Start from the top shingle and rinse downward to prevent water seepage.

Take Precautions

Prevent Roof Mold In Future

There are a few simple ways to keep mold and algae from returning to your newly washed roof. The simplest is to apply a cleaning or treatment product formulated for long-term protection against algae and mold growth. There’s also the longstanding preventative measure of installing zinc or copper strips near the ridge line of the affected roof planes. Both metals contain minerals that naturally inhibit algae and mold. You simply slip the strips under the shingles, leaving the metal partially exposed, and nail the strips in place. When it rains, the runoff water carries minerals off of the metal and washes them down the roof.

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Your Roof Is Moldy Now What

Scientists may think mold is great, but the rest of us have a hard time not resenting it. The stuff grows everywhere, from the cheese in the fridge to the bathroom ceiling to the very skeleton of the house. And yes, it can even grow on your roof. The good news is that moldy roofing shingles, unlike old cheese, don’t need to be thrown out. Here’s how to get rid of roof mold and keep it from coming back.

Will Algae And Moss Growth Damage Asphalt Shingles

Roof Cleaning

Algae will not damage asphalt shingles. It just looks terrible. But moss is a different animalits sponge-like and collects moisture. That moisture then sits on the surface of the roof for an extended period, keeping the roof wet. When this happens, shingles will curl and pull away from the underlayment, which weakens them. In a windstorm, the shingles can get torn off the roof and shorten its lifespan if you dont repair the roof.

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Another Less Common Occurrence Is Moss

If you see green fuzzy stuff on your roof it is most likely moss. Moss loves cool, damp environments. If you have moss on your roof it will be commonly found on the North slopes in addition to overhanging treses or overhanging sections of the roof causing shade and allowing moisture to hang around and the moss to grow.

Moss spores can become airborne and make their way onto roofs via wind, birds, squirrels, and other small animals, in the same way that algae makes its way to your roof.

Once the moss spores land on a roof, they will gather in the spaces between shingles and eventually grow into thick spongy moss.

Algae is a term for a large group of photosynthetic eukaryotic organisms. They are typically aquatic and lack the roots, stems, and leaves of other plants, though they still contain chlorophyllthe green pigments found in most plants. However, they are not plants but rather organisms also spread by spores, much like moss.

Mold is the result of algae left too long on a roof. Algae needs perpetual moisture to exist, so they grow best in humid areas. When algae keeps the roof damp for long enough, rot can set in, commonly leading to mold growing and spreading.

Would You Believe Fungus

Yessiree… the 3M Companyhas developed an additive for asphalt roofingshingles using copper granules. This unique advance in shingle technologygives long-term fungus protection for the entire roof. Theycall it the AlgaeBlock system. You can find more information onthese special roofing shingles HERE.

3M is not a manufacturer of asphalt shingles, just the granules. However, at the time of this writing they do list anumber of companies that are producing shingles meeting their specifications.

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Why Shouldnt I Add A New Roof Over Moss

When you need a new roof, it may be tempting to add a second layer of shingles over your existing shingles. Doubling up your shingles can save time and expense on your roof replacement as your roofer doesnt need to remove and dispose of the old shingles. This strategy is convenient for homeowners because the replacement wont take as long or make as much of a mess. However, there are some circumstances where merely adding a new layer of shingles isnt a good idea.

For example, when you have significant moss growth on your roof, simply covering it up with new shingles isnt wise. Several potential problems may occur if your roofer simply adds a new roof over your existing, moss-covered roof. These potential problems include:

How To Remove Moss From Your Roof

How to Clean and Prevent a Mossy Roof | Ask This Old House

Roof going way too green? Use these materials, tools, and methods to eradicate moss from your rooftop.

Greenery overhead should be limited to leaves flushing out tree canopies. If mossy foliage covers your roof, it’s time to get cleaning. Moss grows in areas untouched by sun, so it can develop at a speedy pace on tree-shaded and north-facing roofs. Spreading moss can quickly upholster to roof surfaces, filling in voids between shingles and tiles and reaching under and lifting up roofing materials. This heaving of shingles allows rainwater and other moisture to seep into a roof’s structure to cause decay and rot.

Before you clean moss off a roof, you’ll need to consider how you want to kill the plants and remove the dead layers of moss. After cleaning, you’ll also need to put some defensive measures into play to prevent roof moss from growing back.

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Guide For Algae & Moss Removal On Your Roof

If you live in the South, Midwest, or another region of the country that has warm, humid summers, you may have noticed stains and streaks showing up on your asphalt shingles. These stains look a lot like moldbut in fact, much of this so-called mold is actually blue-green algae . In some cases, what looks like mold might be more properly classified as moss.

In less frequent instances, the streaks on the roof actually are mold, which can be very dangerous for your family and more difficult to get rid of. The most serious mold cases can cause asthma, headaches, and other health problems, so its crucial to understand the difference.

Mold And Mildew Growth

As you can see, the alga gets on your roof easily enough the wind just has to blow in the right direction and there it is. Just as easily, mold and mildew follow. The standing water and humidity, the rapidly growing spores and wood rot, these are quick and fertile breeding places for mold. This can be expansive, and as a result, expensive. Often the damage is done well before its discovered, as mold on the outside of the house is usually indicative of mold on the inside of the house.

You cant prevent spores of algae and moss or mildew from landing on your roof. But you can prevent growth. Obviously the best care is preventative care. With regular cleanings you can get rid of the algae before it even becomes an issue, and definitely before it gives way to rot, mold and mildew.

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The Dangers Of Mold On Your Roofing Shingles

Mold forms when moisture dwells on your roofs surface. The process usually begins with the formation of small spots that transform into streaks on your roofs plane. Furthermore, mold spreads exceptionally quickly.

According to All Dry USA, mold takes only 48 to 72 hours for it to spread to your homes interior. Here are some of the dangers of mold and why you need to clean mold off roofing shingles.

  • Unattractive Streaks that detract from your homes beauty, taking away its curb appeal.
  • Mold becomes slippery when wet, creating a safety hazard when climbing on your roof for cleaning, maintenance, or leak inspections.
  • Mold weakens your roof, deteriorating the condition of the shingles, causing roof rot, and shortening your roofs life span.
  • Most importantly, mold can be a health hazard to you, your family, and pets if left untreated.

Because of these and many more potential dangers, its essential to take care of mold as soon as possible.

How To Remove Moss From An Asphalt Roof

Soft Wash Roof Cleaning â Phoenix Clean

Q: We have a green roof that is not meant to be green. Moss is collecting on one side of the asphalt roof. The roof is otherwise in good shape. What I have learned so far is that the roof should not be power-washed. How should one remove the growth, and who does this type of work? I am not interested in getting on the roof myself.

Falls Church

A: The Asphalt Roofing Manufacturers Association distinguishes between moss, a plant with leaves that can grow into thick clumps, and mold and mildew, which are common names for types of algae that simply discolor the surface. Algae creates ugly black or brown streaks but doesnt damage a roof. Moss which is what shows in the pictures you sent is more worrisome because it can damage asphalt shingles. A thick growth of moss works like a sponge, keeping the roofing damp for long periods, and it can lift edges of shingles, making them vulnerable to blowing off in a windstorm.

To clean either algae or moss, the association recommends putting on protective gear and protecting plants, spraying with a 50-50 mix of household bleach and water, allowing that to sit for at least 15 to 20 minutes and then rinsing with low-pressure water. The bleach will kill the algae or moss, but rinsing wont necessarily leave the roof sparkling clean. Algae will disappear and wash away with subsequent rains, the association advises. Moss will loosen over time and may be removed with a leaf blower.


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Why Is Moss Bad For Shingles

You may feel that a bit of moss gives your roof some charm, just as ivy growing up the side of your house might. While moss may be beautiful, it is a detriment to your roof. Heres why:

Most plants gather water from their roots, but mosses gather water from their leaves. Therefore, they do not mind that shingles, unlike soil, are a dry and relatively nutrient-free environment. They will grow roots directly into the shingles, which can destroy the shingles and create the opportunity for leaks.

When it rains, moss will soak up water and retain it, creating consistently wet conditions on your roof. Moss growth will also interfere with proper drainage of water off the roof as water needs to trickle through or around the moss instead of running straight down to the gutters. The resulting constant exposure to water can degrade shingles.

Over time, moss can also work its way under shingles, lifting them up. This uplift creates opportunities for water to penetrate lower layers of the roof and, potentially, your home.

While minor moss infections may not cause many issues, it is likely to become severe over time. Once you spot moss growth on your roof, you should take steps to resolve it. If you have a severe infection, you may have no choice but to remove the shingles that have been damaged by it. A professional roofer can help you assess what kind of intervention your roof needs.

Chlorine Bleach Cleaning Mixtures Are One Option

If you’ve had experience with mold and mildew in the home, you know the best mildew remover ischlorine bleach. But outdoor, heavy duty cleaningusually calls for more heavy-duty mixtures such as TSP and chlorine bleach , or specialty additives such as Jomax from Rustoleum, which combines a cleaner with a bleach activator.

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How To Remove Roof Shingle Stains

Black or green shingle stains from mold, mildew, or algae can be unsightly. If left too long, they can also eat away at the asphalt granules and begin to compromise your roofs integrity. Its important to clean away the mold/mildew/algae on your roof here, our roofing experts tell you how to remove roof shingle stains with a cleaner:

A Most Effective Roof Shingle Cleaner

HouseSmarts DIY “Clean Roof Streaks ” Episode 104
  • Written by Tim Bossie on Aug 14, 2010To ensure our content is always up-to-date with current information, best practices, and professional advice, articles are routinely reviewed by industry experts with years of hands-on experience.Reviewed by
  • 20-30

A good roof shingle cleaner can save you thousands of dollars in unwarranted replacement costs. Many times homeowners will believe that when there is a buildup of algae or green growth on the roof shingles, it is time to replace them. However, with careful cleaning you can still retain the old shingles without any damage to the surface.

Cleaning Roof Shingles

Cleaning roof shingles is not something that many people think about. However, it should be done at least every few years, especially if there are any large trees that hang over the roof. Small leaves or seeds fall onto the roof and can germinate over time. Washing the roof down prevents this from happening. Some cleaners are better than others for this process. Knowing which ones to use will help keep the shingles clean and long-lasting.

Use Bleach for Effective Cleaning

Use Sodium Hydroxide

Citrus Acid

Pressure Washer

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Real Estate Investor From Washington District Of Columbia

Mold doesn’t grow on inorganic objects. Sorry to say, but it’s probably growing in the plywood under the shingles and a cleaning isn’t going to cut it.

Blue/green algae can cause that

Copper fungicide is in lawn and garden at lowes or Home Depot

Copper sulfate works

Algae is what I meant. Whatever causes the stains on the shingles.

How Can Homeowners Discourage Algae And Moss From Growing On The Roof

Trees overhanging the roof can encourage algae and moss growth. So trim back any overhanging branches. Twigs, leaves, and sticks that accumulate on the roof should be promptly removed with a leaf blower. Always direct the airflow down the slope of the roof, so debris doesnt get stuck under the shingles.

Keep the gutters clean and clear. If a higher roof is draining onto a lower roof, thats a recipe for algae and moss growth. A simple fix is to direct the downspout of the upper roof into the lower roof gutter.

If youre due for a roof replacement, then installing algae-resistant shingles is an excellent way to prevent unsightly algae growth. Algae hate copper, and you can also put strips of copper under the shingles nearest the roof peak. This will prevent future algae cells from making your roof their home. You can also replace your old asphalt shingles with new ones in a darker color to hide streaks and stains.

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Black Streaks On Roof Shingles

One of the most common stains on an asphalt shingle roof are the black streaks that seem to cascade down the face of asphalt roofs. While these streaks may resemble mold or mildew, they are a specific type of blue-green algae. This type of algae travels by air and can be transferred to your roof from a neighbors roof.

This type of algae loves hot, humid environments. Most commonly found on shingles in the Southeast, it will grow anywhere that experiences hot, humid weather at any time of year. This type of algae will coat shingles and degrade them, trapping moisture on top of the shingle. You can defeat this type of algae with a simple bleach wash, which well describe below.

Preventing Mildew From Forming

Exterior House Cleaning Services
  • Removing overhanging tree branches and allowing sunshine and air movement over your roof. This can eliminate the mildew-friendly environment and stop it from growing.

  • Installing zinc strips under a row of shingles near the ridge of the roof will prevent mildew from forming. The mild chemical reaction caused by rainwater coming in contact with the zinc inhibits the growth of mold and mildew.

  • Applying asphalt roofing shingles containing a copper additive in their surface granules is an option. The copper granules in combination with rainwater have a mild chemical reaction that prevents mold and mildew.

  • Spray-on commercial products that you apply and leave on are also available. Annual application reportedly blocks the growth of mildew.

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