Whats Involved In Roof Cleaning
During roof cleaning, the focus is on killing and removing the algae or moss growth. Chlorine bleach, the same kind you use to whiten laundry or scrub your toilet, is enough to kill off moss and algae spores. The ARMA recommends a 1:1 ratio of bleach to water to clean a roof. They also advise against using a pressure washer on asphalt shingles, as the force of the water can damage them.
After being allowed to sit on the roof surface for up to 20 minutes, the bleach solution should be rinsed away with clean water. A few rain showers should be enough to wash any remaining algae off the roof. The person cleaning your roof might also use a leaf blower to remove any leftover pieces of moss.
Cleaning An Asphalt Shingle Roof
How To Clean Your Roof
There are several ways to clean your roof from moss, algae and mold. Use these tips as your guide when cleaning your roof.
Some homeowners are considering roof waterproofing in order to prevent moisture and mold growth. While its good to initiate for your roofs maintenance, getting help from an exceptional roofing company is still your best option.
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The Effects Of Gloeocapsa Magna
The gloeocapsa magna bacteria makes its way to roof tops as algae spores carried by the wind, squirrels, birds, and even insects. Once on the roof, the bacteria begin to feed on the limestone filler used to create the protective granules asphalt shingles are known for. The bacteria also photolyzes any moisture on the roof to produce oxygen.
Homeowners dont recognize an infestation at first because very little discoloration is observed. But over time, black stains develop as some of the bacteria die off to create a dark, tough, protective outer coating. Gravity pulls this coating down, leaving black streaks on the impacted roof.
Roof Moss Removal: Cleaning Mold Algae & Moss From Your Roof

We don’t recommend trying to handle roof algae and moss removal on your own. We recommend hiring a professional.
If you are a DIY person capable of climbing a ladder and not afraid of heights, you may be able to tackle algae or moss removal yourself.
The safest method for your roof and the environment is to use a product called Spray and Forget or Wet and Forget. These products can be purchased at most local hardware stores, can be put into a hose-end sprayer, and applied in many cases from the ground or a ladder or the edge of the gutter. These methods can take 3-6 months to work but are the safest. Take some time to research these products before use.
Another more aggressive method for quicker results is the use of water and bleach. Below are the general steps for this method:
- Mix 1 part oxygen bleach cleaner with 1 part water.
- Pour the bucket of solution onto the affected area of the roof and let it soak for 30 minutes.
- For larger sections affected by algae or moss you could put this solution into a spray pump and apply. Be extremely careful not to step on wet algae or moss as it is very slippery and could cause a slip and fall!
- After 30 minutes, rinse the mixture off with your hose on a low-pressure setting. NEVER PRESSURE WASH YOUR ROOF. The moss won’t come off your roof immediately, but within a few days, it will dry up and blow off with the wind. If your roof is pretty well-covered in moss, you might need to use a leaf blower to get rid of the remains.
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Asphalt Shingle Roof Cleaning: What Not To Do
Cleaning a roof is a simple process, but there are easy ways to seriously damage your roof. Therefore, it is prudent to avoid the following when cleaning your roof:
- Never use a pressure washer.
- Spray roof from top to bottom. Spraying from bottom to top will force water up and under your shingles.
- Do not clean in the winter, as you risk having excessive amounts of water freeze on your shingles. Freezing water is expanding water, which means water could travel up and under your shingles.
- Dont let bleach or vinegar stay on your roof indefinitely. Vinegar or bleach left to sit can permanently disfigure your roof shingles or cause them to degrade prematurely.
How To Use Bleach To Clean Other Types Of Roofs
Some types of bleach for instance oxygen bleach, can be used to clean other types of roofs. It is environment friendly and it does not damage the color of the roof on wooden roof shingle shakes. This procedure requires the bleach and water
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How To Apply Wet & Forget Hose End
Eliminating black algae with Wet & Forget Hose End couldnt be easier. Simply:
Be very careful walking on your roof surfaces may be slippery. If you dont feel safe on your roof, call a professional.
Try Wet & Forget Outdoor to erase black streaks and love your roof again! Stop by our website to learn more about our easy solutions to everyday problems so that you can spend less time cleaning and more time enjoying life!
Clean Your Roof With A Bleach/water Solution
If you want a clean roof on a budget, there is still a way to clean your roof without using a power washer.
Heres how you can achieve a clean roof and happy home:
- Cover all vegetation and landscaping
- Wear eye protection, rubber gloves, and wear slip-resistant shoes
- Check your shingle manufacturers website for specific cleaning recommendations
If you are looking for a roof cleaning solution to get rid of algae, heres what Bob Villa recommends:
- 1 cup of trisodium phosphate
- 1 gallon of bleach
- 5 gallons of water
Spray your roof down with this solution from top to bottom, allow it to soak in for 15-20 minutes, then rinse.
Go slowly and use even strokes to achieve the cleanest roof possible.
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What Causes Roof Stains
Roof stains can vary, but most of the time they are seen as dark black streaks running down the north side of a rooftop. These can take a beautiful black, asphalt-shingled roof and make it look dingy, old, and in need of replacement.
The real culprit, though, is blue-green algae that grows on asphalt shingles, leaving its mark in the form of an unsightly stain on rooftops. This is a major problem, especially, in areas that are humid. The algae travel through spores in the air and often affects several houses in a subdivision at a time.
It feeds on the limestone that exists in black asphalt shingles, and is usually apparent most noticeably on the north side of a roofthis is because the north side of a roof usually receives the least amount of sunlight, and also remains damp the longest because it takes longer to dry out from rain or other moisture.
Because algae not only threatens the aesthetics of your home, but also the structural integrity, its important to utilize roof stain removal techniques to get rid of the stains.
What Is The Algae On Your Shingles
Diagnosing what treatment to use when roof cleaning is as simple as taking a walk through the property with a professional. A professional will be able to take a look into what is actually growing on your roof, and will know the correct application in order to treat the algae and the amount of time it will take to remove it.
Lets talk about the two types of algae we come in contact with on a daily basis.
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Black Or Green Roof Stains
Roof shingles have a tendency to grow a certain species of algae, which typically appears in streaks or patches of slime ranging from blue-green to dark black. Algae generally doesnt pose a threat to the roof, and its not harmful the way mold could be.
According to experts, algae stains can be removed by using oxygen bleach. You can also opt for a solution of trisodium phosphate applied by low-pressure wash. However, for your safety, its best to enlist a professional roof cleaning service for this job.
When it comes to prevention, you can ask your to add small sheets of copper or zinc to the high points on your roof. This way, water can wash the metallic atoms over the rest of your roof when it rains and in the process get rid of the algae.
Do My Shingles Need Cleaning

If your roof has black streaks, white-looking spots called lichen, or moss growing on it, then it needs to be cleaned. Failure to do so can cause the top asphalt layer to degrade prematurely. Moss growth will cause shingles to curl upwards, creating a greater chance of wind and water damage.
If your roof has any of this type of damage, exposing the roof to the sun by removing foliage will not solve the problem. Increased daylight will indeed mitigate the growth of moss and algae, but once it has grown, it will not simply disappear. It must be removed chemically.
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Are Roof Stains A Problem
Everyone can agree on one thing: roof stains take away from your homes aesthetic value. But will roof stains cause you problems purely on a purely functional and practical basis?
Well, not AT FIRST.
The thing with those unsightly black streaks is that they make the roof a breeding ground for lichen or moss. If allowed to thrive, these critters can cause the asphalt shingles on your roof to rot or decay faster. As the algae feed on the limestone, they wear away at the light-reflecting granules on the asphalt. Once those granules have been whittled away, you might as well bid your roof adieu.
In other words, allowing roof stains to thrive on your roof is one good way to shorten its lifespan.
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Cleaning Roof Shingles With Bleach
When you are thinking about having that nasty algae removed from your roof, consider hiring a professional someone who is used to using chemicals around high end landscape and will take care of your house as if it were their own. Great care should be taken when starting down the road of getting your roof cleaned, as the dangers of killing any landscaping are high if the person does not understand their chemicals capabilities and does not understand their rinse process completely.
After you inspect where the gutters exit and you confirm that they dont exit directly into any plants or trees, you can begin with the next part of the process. Chemical Ratios.
Since the most common form of algaecide used in the professional pressure washing industry is 12.5% Sodium Hypochlorite , the next few sections are going to explain exactly what chemical ratios you are going to want to use when cleaning roof shingles. The mixtures below are going to range from most concentrated to least concentrated and I will also explain why you would choose to use either.
Ps: Consumers are only going to be able to purchase bleach at the hardware store at 6.5%
So after you have your pool shock and water mixed in your garden sprayer, we are going to climb on the roof and start delivering the goods to this algae.
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Dos And Donts: The Best And Worst Ways To Clean A Roof
If youre reading this, chances are youre looking for roof-cleaning tips because your shingles are no longer looking new and attractive. If your roof appears dark and discolored in some areas, you may think that mold has developed on the surfaces of the shingles. However, the black streaks youre seeing are really colonies of blue-green algae. If youre noticing thick, green patches on your roof instead, then youve got a moss problem, The north, west, and shady areas of your roof are most susceptible to these moisture-loving nuisances.
Moss and algae spores are carried by the wind or animals from rooftop to rooftop, which is why entire neighborhoods are often affected. Moss can seriously impact asphalt shingle performance by causing them to curl up and blow off, eventually resulting in leaks. While algae doesnt actually harm your roof, it can impact its aesthetic appeal. Further, climbing on your roof frequently to clean off growth CAN damage your roof and shorten its lifespan by loosening the granules on your shingles. So, its best to know how to clean your roof properly so that you ensure you dont have to do it too often.
Knowing this, what are the best ways to clean a roof of algae and moss growth? Read on for our best roof-cleaning tips!
What Algae Is Growing On My Metal Roof
The first question to ask is, What in the world is growing on my roof and turning my roof black, green, orange, or any color besides what it is meant to be? We highly recommend calling a roof cleaning professional and walking the property and identifying exactly what is growing on your metal roof and creating a plan of action to clean it. There are several types of algae that thrive on a metal roof surface.
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Question: White Stains On Roof
Deborah said:
I have a new roof with architectural shingles that has a white discoloration on it for the moment it was installed. The roofer said it was back surfacing mineral and would wash away. It has been months now. It has faded, but not completely. It is most noticeable when the sun goes behind the house in the afternoon. In the morning, it is barely noticeable. He said it will weather off. Is this true?
Reply:
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Best Solution To Clean Metal Roof
Before you learn this step, definitely consider hiring a highly skilled professional as your roof is probably one of the most expensive investments you make on your home and would be worth its weight in gold to have it cleaned professionally, safely, and effectively. The active ingredient we use and recommend is Sodium Hypochlorite. Most hardware stores keep Sodium Hypochlorite in jugs at 6.5% as that is the highest concentration they can legally sell to the normal consumer base. We get the product for about half the price as consumers can get it for as we purchase in large quantities and we also get a contractor discount because we buy so much. Also the concentration we are able to get is around 12.5% and is labeled as Sodium Hypochlorite/Pool Shock anywhere it is stocked. So here are the ratios for cleaning your metal roof.
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