Ed Thompson Google + Thompson Roof Cleaning Edison New Jersey (732) 726-9261
What Is Growing On Your Roof And What To Do About It
The three main organisms that create stains on a roof are moss, algae, and lichen. All three reproduce by releasing spores into the air. They’ve been landing on the shingle since day one. It doesn’t choose where to land. It lands everywhere but will grow where’s there’s less sunlight. These shady, low-sunlit areas retain more moisture to promote moss and algae stains. The stain can usually start with small clumps of moss and/or some form of black staining. The black staining is a bacteria and not an algae as was originally thought.
As the stain grows it retains even more moisture allowing it to support even more growth. One can expect an explosion of growth at this point. All of these organisms create firm root systems into the roofing shingle. When addressing the growth you have to consider eliminating the growth at the root source in order to fully kill the growth. Pressure washing does not eliminate the roots. Moss on a roof is not much different than a weed in the sidewalk. How much success can one have by simply snipping the weed at the surface? Now take the same weed and soak it with a good weed killer. Eliminating the weed at the root will insure its inevitable demise without return. This is the same concept with the roof.
Considering these spores land everywhere suggests a higher rate of success by treating the entire roofing area. It is good practice to treat the entire area to avoid having other areas catch up a short time down the road. Treating the entire roof allows the clean sides to remain sterile and free of the spores that can regenerate into roof stains.
Let’s break it down to help decide which roof cleaning is the right one for you. There are 3 primary types of roof stains: Moss, bacteria (black stains), lichen, and algae. The black streaky stains that develop on a roof is a bacteria called Gloeocapsa Magma. This hardy pest is actually green when seen through a microscope. The dark pigment is part of a UV repellent shell it creates to protect itself from harsh weather conditions like winter and long periods of heat or drought. A disinfecting detergent with the proper ph level can dissolve the outer shell. Using a means of high pressure water without the use of a detergent with a disinfecting property will not fully sterilize the roof. It can create a “perception” of clean since it took off a majority of the stain, but there could be hundreds of thousands, if not millions of live spores that are left behind that cannot be seen. In this case the stain should be visible within a year or two.
The other danger of having a roof pressure washed vs. a chemical cleaning is power washing a roof will dislodge many of the roofing granules that protect the shingle. These granules are important to protecting the underlying membrane of the shingle. Without these roofing granules the roofing shingle would rapidly deteriorate from suns UV. These granules come off easily. Any gutter will always have some amount of granules that dislodge with wind and rain. I would suggest not letting anyone on your roof with any type of device that is hooked up to a motorized pressure washer. Even if they tell you its low pressure it is probably too much for the roof, and not so much the shingle but the roofing granules. A typical garden hose should support 40-60 psi, some cases higher (or lower). With the right garden attachment you can create some force. This should be the most pressure used on a roof. Pressure washing should stay out of the equation.
Once the roof is fully sterilized and all the bacteria is dead and dissolved the roof will stay clean for many years. When the roof was new it was completely sterile, starting from ground zero. This approach is more like “pest control” rather than a cleaning.
Moss is a soft plant that grows in moist conditions. Moss can cause a moderate amount of damage in the long run by its root system which slowly tear through the shingle. This process is slow but sure. It can shorten the life of a roof by a few years. This is why many insurance companies require some roofs to be free of moss and other organisms. They do not want to insure a roof that is bound for deterioration.
Lichen is a fungus and algae combined to make a super fungus. Lichen causes the most damage to a roofing shingle. Lichen can be found on tree bark or on smooth stone near a river bed. If you have it on the roof it shouldn’t be hard to find on the side of trees. Challenge yourself to try and remove lichen from the tree bark. You’ll find it doesn’t remove easily and if it does the bark may come with it. The same goes for the roof. Lichen eats a crater into the shingle. It devours the limestone in the shingle. Limestone is an organic natural stone that is used as a filler of the shingle. This is the food source for the lichen. A roof can become an “all you can eat buffet” and suffer scars if not addressed in time.
Learn more about roof cleaning and soft washing in this video
Is a chemical cleaning safe for my home, family and pets?
Nobody likes the sound of chemicals sprayed anywhere near there home. The products we use are safe and as effective as any household cleaner. “Earth-Friendly” products are just that. They will not kill the moss at the root. If it does not have the ability to kill the growth on the roof there cannot be any long lasting cleaning. Thompson Roof Cleaning and Power Washing LLC uses a chemical cleaning method when treating roofs for moss, mold and other stains. One detergent fits all and creates our desired effect. Moss and lichen will decease quite easily. The detergent is calibrated towards the most difficult staining which is bacteria (blacks stains). The black staining will not dissolve unless the ph level of the detergent is high enough. We achieve this by using sodium hypochlorite. Common house hold bleach is sodium hypochlorite. “Pool shock” is sodium hypochlorite. Municipal water treatment facilities are the largest purchasers of sodium hypochlorite. It is used to treatment our drinking water. It is a non-carcinogenic, non-flammable products that is safe when used properly. Sodium hypochlorite (or bleach) is made by using sodium chloride (or table salt). Bleach breaks down quickly which makes it a truly biodegradable product. If you pour bleach in a cup and returned when the liquid evaporated you will see salt crystals left behind. Bleach starts as salt and ends as salt. This makes bleach the safest and most effective sterilizing agent. No, I wouldn’t go drinking the stuff but it works.
This isn’t even the best reason to use sodium hypochlorite (or bleach). Bleach is recommended by the shingle manufacturer themselves. Take the most popular Timberline shingle and their manufacturer GAF. Instructions on their own website warn against pressure washing and suggest using a detergent that contains bleach. Bleach is completely compatible with the shingle. Let’s refresh what we’re trying to do here; Just like anything else with an illness the cure lies with eliminating the parasite while protecting the host. We achieve this since we do not scrub or pressure wash the shingle. Our detergent applies as a wet foam. We add a surfactant to our detergent which breaks the surface tension of the shingle and allows the medicine to get to the root of the matter and completely sterilizes all living organisms that are creating the stain. We failed our objective if we are too aggressive and blast the roofing granules from the roof. The granules come off very easily just by rain and wind. Check you gutter and you’ll always see granules inside. Pressure washing can expedite the granule-loss process.
There is no instant gratification
Moss and lichen do not remove quickly. We clean roofs with a disinfecting detergent that kills and sterilizes the organisms. Moss and lichen are treated and die within minutes, but it is not removed instantly. Moss and lichen develop a root system into the shingle and should not be removed forcibly by scrubbing, scraping or pressure washing. Once it dies it will decompose and dry out. The root system will detach on its own. The moss and lichen will wash away little by little. This process averages 90 days until the roof is fully cleaned. It’s similar to spraying a weed with weed killer then walking away.
Thompson Roof Cleaning is a proud member of good standing with the National Soft Wash Alliance. See their video to see why it benefits you to use an authorized NSWA cleaning contractor:
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