Tips To Prevent Roof Algae & Moss
Roof algae and moss usually grow because of moisture and bacterial growth. You can stop that growth from ever starting in the first place, effectively making your roof last longer. Here are a few ways to prevent future growth once you have gotten rid of moss and algae:
- Trim trees near the home: Overgrown trees often spread bacteria onto the roof and cause algae growth. Make sure to plant trees far enough away from the house and trim them back regularly so they arent hanging over the roof.
- Get rid of standing water: Standing water is another factor that can contribute to mold and algae growth. Minimize standing water on the roof by fixing shingles, cleaning gutters, and performing small roof repairs as necessary.
Preventing Mildew From Forming
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.
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!
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Algae & Moss Prevention And Cleaning For Asphalt Roofing Systems
Maintenance Solutions
To understand how to deal with the recurring problem of algae and moss growth on rooftops, it is important to learn what they are and how they grow and spread. Although some similarities exist, algae and moss are very different and require slightly different procedures to prevent or to remove.
Often mistaken as mold or mildew, the black discoloration and streaks visible on many roofs across the United States and Canada are actually algae. The algae can form w here moisture tends to dwell on roof surfaces. Coastal or humid climates create the most conducive conditions for algae growth. The most common type, gloeocapsa magma or blue green algae, protects itself from damaging ultraviolet rays by producing a dark pigmented sheath. The algae discoloration typically begins as small spots then quickly transforms into streaks on the roof plane. By the time the algae is visible, it likely has been present for several months or longer.
Moss is a non-vascular plant that obtains water through its leaves, unlike most plants that gather water through its root system. Moss must therefore have a moist environment to survive. In North America, moss tends to grow on north facing roof planes that receive less direct sunlight and stay damp longer than south facing planes. Overhanging tree branches provide additional shade and drop debris on the roof that further holds in moisture and acts as a food source for moss.
How To Clean Algae Or Mold Off Your Roof Shingles
Living in a humid area of the country like Florida, youve probably seen your asphalt shingle roofs with unsightly dark streaks on them. A blue-green algae known as Gloeocapsa Magma could be the reason you have the algae which is spread by airborne spores. Sometimes it can also be caused by an accumulation of mildew, mold, dirt, or defective shingles.
This discoloring can hurt the beauty of your homes curb appeal and the resale value of your home if you have it up for sale.
Algae stains dont show up below the metal flashing around chimneys or roof vents because the copper and the zinc coating on galvanized sheet metal are toxic to algae. Whenever it rains, trace amounts of metals are washed down the roof, inhibiting algae growth.
Algae Resistant Shingles
In recent years, roofing manufacturers have begun mixing copper granules into roofing products to produce algae resistant shingles. If you live in an area susceptible to algae growth, be sure to specify this type of shingle when replacing your roof, reports Todays Homeowner.
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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.
Stop Roof Algae From Coming Back
To keep the algae from coming back, insert 6-inch-wide strips of zinc or copper under the row of shingling closest to the roof peak, leaving an inch or two of the lower edge exposed to the weather. That way whenever it rains, some of the metal molecules will wash down the roof and kill any algae trying to regain a foothold on your shingles.
You can probably see this same principle working on roofs in your neighborhood. Look for chimneys with copper flashing the areas directly below the flashing will be free of any algae stains.
The strips also work on roofs suffering from moss buildup. Just scrub it off first with a brush, then bleach as above.
Need help with home maintenance? Read our reviews on home warranty providers.
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Roof Cleaning With A Pressure Washer
Some may believe that you can clean your roof simply with a pressure washer, and while that would probably work theoretically, using a pressure washer for roof cleaning is the kiss of death for the integrity of that roof. Especially if you are trying to clean an asphalt shingle roof. The granules will start to come off and will end up in the gutters, which can and does happen normally with age, but speeding up the aging process for the roof, is not the best idea and is something we avoid.
How To Use Bleach Mixtures On Your Roof
The following procedure is for bleach-cleaning only using JOMAX. If JOMAXis not available in your area, use a TSP mixture with bleach added.
If you think it wise to leave the bleach-brew on the roof longer than therecommended time, thinkagain! As mentioned earlier, long term exposure to bleach can damage most any surface, and yourroof is no exception. However, this piecemeal approach is the likelyto cause the least damage.
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Two Common Types Of Algae On Your Roof
Fire Moss – Fire Moss is less common than the Gloeocapsa Magma below but is still very prevalent on many roof substrates, from cedar shake to asphalt shingles, it loves to latch on and reproduce. When fire moss gets out of hand, it will push up your shingles allowing water to get underneath and severely degrading your roof.
Gloeocapsa Magma – This is the old “black streak on my roof” culprit. It is most common on Asphalt shingles and can is a spore based algae, it lives on the limestone in your shingles. When it feeds it degrades the limestone and eventually if left untreated, will take over the whole roof making it look all black when that is not the color of the shingle itself, that is in fact the algae growing on the shingle.
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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How Can Leaks Be Repaired
You can call a professional to do roofing repairs, but if the damage is minor, you might be able to fix it yourself. Here are some points if you decide to do it yourself:
- Locate the leak source by standing in the attic and looking for wet spots.
- Tie a string to a nail on an upper rafter.
- Pull the string across to lower rafters until it reaches the wet spot.
- Go into the attic and cut a hole in the roof around each chalk mark.
- Patch the hole with roof cement.
- Replace the shingles around the hole.
- Repeat this process in each wet area.
What Are The Black Streaks On My Roof
Many home owners are surprised to discover that the once clean asphalt roof shingles have been slowly covered with a form of roof mold or mildew that appears as a light discoloration and spreads down the roof toward the gutters. The black roof stains are caused by a form of algae that has been around for years, typically found in the woods on the north side of trees, or on exposed rocks but now this black algae is termed a roof shingle algae because of the annoying discoloration on a asphalt shingle roof.
The roof algae actually feeds on the crushed limestone that is present in shingles from most asphalt shingle roof manufacturers. The roof algae is spread by wind and animals from roof to roof and is almost impossible to prevent.
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Avoid An Expensive Roof Replacement By Easily Removing Moss Algae And Mold From Your Shingles
- Remove moss, black algae, mold, lichen or any fungus that may grow on roofs and eat away at your roof shingles
- Safe and effective for asphalt, metal, tile, wood shake, rubber and new composite roofing materials
- Feel confident knowing our product wont harm your children, pets or landscaping!
If you are looking for a safe, effective way to clean to clean stains or debris caused by algae and moss from your roof without harming your pets or your landscaping, our Roof Wash is exactly what you need. We field tested and perfected our formula over years in the roof cleaning industry and as the manufacturer, we stand behind the efficacy and safety of our product 100%.
Add 125 ml of Oxy All Roof Wash to 4 L of water. If available, warm water dissolves best. Mix well, stirring frequently, then allow solution to fully activate for 15 minutes before use. To clean without rinsing, spray on with a garden style hand pump sprayer, and leave it to mother nature to wash off the debris. Damage is stopped, but it may take 60 days or more to come fully clean. In some extreme cases a second application may be required. For an immediate clean roof, apply to small enough sections that can be kept wet, scrub with a stiff brush, then rinse with a hose. For a professional type cleaning, spray the roof completely then rinse with a pressure washer set at less than 1000 psi .
Avoid letting overspray dry on glass as it leaves a difficult to clean residue.
Active ingredient: hydrogen peroxide
How To Remove Black Roof Stains
Our home is 10 years old and the asphalt roof shingles are starting to stain badly on the north exposure. Is there something that we can use to clean off the staining and treat the shingles to prevent further staining?-Tim
Hi Tim,
Your stains are probably caused by the airborne spores of a blue-green algae known as Gloeocapsa Magma, which is often mistaken for mold or mildew. While doing little harm to your shingles, the black streaks caused by the algae are unsightly.
Algae can be killed and the stains removed using chemical cleaners, though they usually return over time. Use a cleaner specially made for killing algae, or by spraying a mixture of one part bleach to four parts water with TSP or other detergent added in a garden pump-up sprayer. Allow the bleach to remain on for 15 to 20 minutes, then rinse it off with a hose.
Note that bleach may kill or damage plants, so wet down or cover any shrubs or flowers that will come in contact before starting. Repeated use of harsh chemicals or pressure washing can damage or shorten the life of your shingles.
Once the roof is clean, consider installing strips of zinc or copperwhich are toxic to algaealong your roof below the ridge. Molecules of the metal will then wash down the roof each time it rains to keep new algae from forming. A better solution is to specify algae resistant shingles, which have copper granules embedded in them, the next time you have your roof replaced.
Good luck with your project,
- TAGS
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Assemble A Team And Get To It
Three hardy people can tear off and felt a roof in one day, but be careful. Only tear off what you can safely protect from the weather the same day, especially if youre working shorthanded. It always takes longer to weatherize than you think! Tear off the areas farthest from the trash container first. That way you wont tear up the new felt paper when you haul the rest of the debris to the container.
Go over the wood surface with a fine-tooth comb after tear-off. Pound in protruding sheathing nails and remove any leftover shingle nails, then sweep and install ice and water barrier and felt.
What Are The Dark Streaks On My Roof
You may have noticed dark streaks across your roof. Given that moss grows upright on surfaces, and algae stays low and flush to the surfaces it grows on, its likely any dark streaks you see are algae.
Algae staining on roofs all start out being spread by wind, birds, and varmints, affecting homes across much of the United States.
This algae normally begins its lifecycle as airborne spores that will settle on your roof, especially those roofs that have asphalt shingles. The northern exposure of roofs has the most chance for algae to survive/thrive because that part of the roof is exposed to the least UV and dries last after morning dew and rain.
As the algae grows and spreads, it begins to look like large black streaks on your shingles.
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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.
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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