Keep An Eye On The Sky And Your Roof
There are maintenance practices no matter the type of roof you should employ. First, pay close attention to the weather, especially if you live in an area prone to severe storms like hurricanes or hail. You should perform your own visual inspection both before and after a storm. Walking a rooftop may seem like the sensible way to inspect a roof, but it is a very dangerous. Even among trained construction professionals, falls are the leading cause of jobsite fatalities. For this reason, CertainTeed cautions homeowners to only inspect their roof from the ground by using binoculars for an up-close view, or from the top of a ladder while being mindful of ladder safety practices. Look for shingles that are damaged, loose, or missing also, do the same for flashing. Flashing is a thin material, typically made of galvanized steel, installed to direct water away from areas where the roof plane meets a vertical surface like a chimney or dormer.
Additionally, you should check your roof from the inside by going into your attic space right after wet weather, and looking for signs of leaks. These include water staining on the rafters or roof decking , wet insulation, or mold growth.
If you spot any trouble signs, contact a local roofing professional for further assessment. No matter the extent of your roof damage, its important to leave roof repairs in the hands of professionals.
Difference Between Moss And Algae
Though they might be grouped as the same thing because they grow in the same area of your home, moss and algae are actually quite different and distinct.
Moss always appears more green and fluffy-looking than algae, though it might appear browner during dryer seasons. Moss will also grow up off the roof, while algae will grow flush to the shingles and fixtures, staying flat and unobtrusive. Algae will appear in many different colors such as gray, blue, green, or brown.
A small amount of moss is relatively harmless, but left unattended, it can grow and eventually damage your asphalt shingles. Moss should be removed. Algae actually fosters the growth of mold, which can lead to very serious issues. Algae, too, should be removed quickly and efficiently.
Can I Use A Pressure Washer On A Metal Roof
The absolute very LAST technique you want to use on your metal roof is the strictly high pressure washing method with a high pressure tip and damaging pressure washer. A metal roof is very strong against many earthly elements but highly pressurized water or high pressurize anything is not recommended! In fact, pressure will not even do anything for you as far as cleaning the roof is concerned. A metal roof is constructed seamlessly or with screws and those screws have a rubber gasket and the high-end screws have a metal cap over the gasket for extra protection. Pressure Washing can damage these screws and expose the weak areas of your roof causing roof leaks in your metal. High pressure can also damage the finish on the roof as all roofs are made of different qualities, metal compositions, and more variables. The optimal amount of pressure you want to use when washing a roof is around 100-300 PSI and preferably HIGH-FLOW & LOW-PRESSURE. We consider HIGH-FLOW approximately 8 gallons per minute of water flow or greater.
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How To Remove And Prevent Black Algae Stains On Asphalt Shingles
You have probably noticed that asphalt shingle roofs often have unsightly dark streaks, especially if you live in a humid part of the country. People usually think these streaks are caused by things like defective shingles, mold or mildew, or dirt, but in reality, it is caused by Gloeocapsa Magma, which is a blue-green algae that is spread by airborne spores.
This algae does not necessarily harm your roof, although it does affect the appearance of your roof and thus, diminishes your homes value.
You wont likely see theses stains just below the metal flashing on your vents or chimney because galvanized sheet metal has a copper and zinc coating that is toxic to algae. When it rains, the algae is washed away by a trace amount of these metals, which inhibits the growth of algae.
Do It Yourself And Save Big Bucks

Professional roof cleaners charge hundreds of dollars the bigger the roof, the more hundreds youll spend. And they have to repeat the cleaning every few years. If your roof slope isnt too steep and youre comfortable working on it, you can clean it yourself and save the dough.
Youll need a full-body harness, a garden sprayer, a garden hose and a nontoxic, noncorrosive roof-cleaning chemical. Some manufacturers sell a special tool applicator and rinsing tool, but if the staining isnt severe, you may not need them.
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How To Clean Mold Off A Roof
This article was co-authored by Mike Kapur. Mike Kapur is a home inspector and the owner of Sonic Home Inspections, a home inspection company in Westchester, New York. With over 15 years of experience in pre-inspecting properties, Mike specializes in mold, radon, asbestos, lead, water, and air quality testing as well as hazardous materials, pest, infrared, and general home inspections. Prior to founding Sonic Home Inspections, Mike worked pre-inspecting apartments. Mike holds a BS in Accounting from Queens College and is a Certified Mold Assessor in the state of New York.There are 17 references cited in this article, which can be found at the bottom of the page. This article has been viewed 62,781 times.
Its easy to let a mold problem sneak up on you on in out-of-the-way places like the roof of your home. Just because you cant see it, however, doesnt make it any less dangerous. At best, slimy black mold deposits are an eyesore at worst they can pose serious health risks. Thats why if you find evidence of mold growing on the roof of your home, eliminating it right away should be a high priority. You can bust up stubborn mold, along with other types of growth like moss and algae, by spraying your roof down with a powerful chemical cleaner.
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
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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.
Choose A Safe And Effective Product To Clean Asphalt Shingles Without Damaging Them
The first step in maintaining your roof is to roof it right. If youre not doing the work yourself, choose a qualified professional roofer to do the job. And choose your roofing material wisely. Some roofing will require less maintenance than others. Choices include metal and slate. Some roofings types last longer than others, as well. That said, data shows that you are probably going to choose asphalt shingles, which can last a lifetime, but likely not without some repairs and maybe replacing a few shingles here and there. And, you may need to clean the roof once in a while.
Twenty years ago I bicycled about 500 miles along the Oregon / Northern California coast and marveled at the number of asphalt shingle roofs carpeted with lichens and moss. The roof growth gave character to many seaside and forest cottages. Though the roofs looked cool, I knew the shingles probably wouldnt last too much longer.
Lichens and moss accelerate shingle deterioration by loosening shingle granules and exposing the asphalt and fiberglass base materials. The granules arent just there to color the shingles they protect the base materials from sunlight and weathering.
About five years ago, I noticed a few patches of lichens growing on the north side of my roof. Like most lazy homeowners, I ignored the problem. Then about two years ago, when the roof looked like those out in the Pacific Northwest, I knew I couldnt put off treating the growth any longer.
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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 today and love your roof again! Stop by our website to learn more about our easy solutions to everyday problems, so you can spend less time cleaning and more time enjoying life!
Spraying Cleaner And Scrubbing Shingles
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Benefits Of Hiring A Roofing Contractor
Mold is typically the result of algae growth. Mold spores can easily become airborne, jumping from roof to roof. That is why you may see a mold problem in a certain neighborhood. Certain conditions are more favorable for mold, such as roofs with leaks or wood rot. Oftentimes, the presence of mold is a sign that there other roofing problems exist. While you may not visibly see roof damage, that does not mean that damage does not exist. When you call in an experienced roofing contractor, underlying roof problems may be found. Making these repairs can reduce the likelihood of mold growth in the future.
What Causes Black Streaks On Roof 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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Preventing Reinfestation Zinc Strips Are One Option
If you wish to prevent reoccurrence of fungus, think zinc! Zinc strips have been used for many years as an algae preventative. StainHandler.com offers sets of 3′ zinc strips, which areattached near the peak of the roof. When it rains, a slight amount of zincdissolves from the strips and coats the roof, inhibiting algae and fungusgrowth.
Why Bleach Or Pressure Washing Arent The Answer
Some homeowners turn to bleach or pressure washing to clean roof stains, but they arent the best option for cleaning black algae on asphalt shingles. Bleach is a caustic chemical that runs the risk of corroding your homes downspouts, damaging your lawn with caustic runoff, and even causing some shingles to prematurely shed their protective granules.
Using bleach on black algae also requires brisk scrubbing and rinsing, which makes it a pretty work-intensive job and can also increase the wear and tear on your roof.
If you pressure wash your roof, the force from the water can cause your shingles to shed their protective granules, tear shingles loose from the roofs membrane, knock your downspouts out of whack, and force water into spaces where it doesnt belong.
After all of that hassle, these methods fail to reach the root of the stain and even leave a food source behind, which can cause growths to come back quicker and thicker. This means you will be back on your roof with the bleach and scrub brush or pressure washer, again and again, stuck in an endless cycle of cleaning and re-cleaning.
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Removing Moss Mildew Fungus And Associatedstains On Roofs
Roof cleaning is a topic that draws yawns in New England but causes shudders andscreams of agony from Florida and points south, where vegetable life seeksworld domination! How do we keep that “fungus among us” under control.
Since starting on a quest for the ideal method of cleaning fungus and algaefrom roofs, I have contacted dozens of individuals and companies. Some of my readers came forwardwith suggestions and a few companies also supplied information helpful to thisresearch.
For the purposes of this article, the terms “mildew”, “fungus”, “algae” and”moss” are interchangeable… even though their mothers’ might object!
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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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.