Roof Cleaning: How To Clean A Roof
You've pulled into your driveway and for the first time you take notice. What are those horrible black streaks covering my roof? Perhaps reading this lens is the first time you have even thought about your roof in a long time. Go outside and take a look. We'll wait...
Okay. If you are like 90% of homeowners or business owners and your roof is more than 5 years old, you saw some type of growth. Before we get into what the growth is, it may best to describe how it looks. Did you see black streaks? How about any green growth? Perhaps you noticed lichen growth, little colonies that resemble a mushroom cap. Take a look at the picture to the left. Those are the black streaks in the top portion. Obviously there is a solution as you can see in the "after" picture. No Photoshop or trick photography. That is the same property after having a professional roof cleaning . Now its time to learn how to save your roof!
What Is On My Roof?
In short, it is a cyanobacteria called Gloeocapsa Magma.
From Wikipedia:
"Gloeocapsa magma is a species of cyanobacteria. Cyanobacteria are an ancient line of photosynthesizing bacteria, which photolyze water generating oxygen gas. Ancient cyanobacteria were ancestral to the chloroplasts of all plants on earth. Gloeocapsa magma has gained notoriety in the Southeastern United States which is spreading throughout the Midwest. This particular type of cyanobacteria is responsible for creating black stains and streaks on roofs. The bacteria accumulate over time as it feeds on moisture and calcium carbonate. This accumulation begins to show the black stains as the cyanobacteria develop their dark and hard UV-protective outer coating."
The main sentence that I would like to focus upon includes the statement "feeds on moisture and calcium carbonate". Have you noticed the growth is worse under trees or on the north side of the building? These areas are generally more shielded from the sun and retain moisture for a longer period. Calcium carbonate is in your shingles. Mold also feeds on carbon and oils. There is even more of your shingle being eaten. Will your shingles be destroyed over night? Not at all. The degradation is very slow. Some may argue roof cleaning is for purely aesthetic reasons. Perhaps that is true, but I suppose it depends upon how much of a gambler you are. On the betting table is your $10,000, $20,000 or $30,000+ roof. Clean your roof for aesthetic reasons and curb appeal and slowing the deterioration of your shingles may be a side benefit.
Methods For Cleaning A Roof
Temporary fix or long term solution?
Your roof takes the brunt of abuse from the weather. It has to be strong to resist heavy rain, snow, and constant bombardment of UV rays from the sun. This does not mean your roof is indestructible. Asphalt shingles have a coating of mineral granules. This is the main protective coating against the elements. It also gives a shingle its color. These granules can be disturbed by simply walking on a roof. Pressure washing a roof with anything over 300 psi (not 3000 like most machines output) is a guaranteed way to blast away a substantial portion of that protection layer.
So immediately you can understand why I mention that hiring someone that is not a roof cleaning professional may not be in your best interest. High pressure not only will damage your roof, it doesn't really clean. It may take off the surface mold off the roof and appear clean but below the surface, Gloeocapsa Magma and any other mold spores are waiting for a little water and a few cloudy days to begin growing actively. Like chopping a weed off at the surface, pressure washing a roof with no fungicide is a very temporary fix. Professionals will use specialized cleaners that actually kill all chlorophyl sustained life. This gives you a long term solution for your roof's problem.
Bleach For Cleaning My Roof?
There are firms that are making claims against the use of sodium hypochlorite (the active ingredient of bleach) claiming the potential risk of damage to landscaping. Their claims are not unfounded but can be considered suspect. We'll revisit that in just a second. First, let's address the potential damage that can occur to sensitive plant life...
Bleach, in too strong of a dilution, can harm plants. Professional roof cleaners should make precautionary procedures a priority. Within the properly equipped roof cleaning contractor's arsenal are tarps, a ground man to keep landscaping watered and diluted and diversionary tubes or bags at the bottom of downspouts. Be diligent when questioning your contractor. How are they promising to keep your property protected? A good roof cleaner will bring an expensive array of chemical application pumps, safety harnasses and hose that is resistant to rupture. The right roof cleaning company will spend just as much time taking care of what's on the ground as they will on the rooftop.
Surface Cleaner On A Rope
The reason I mention that claims against sodium hypochlorite are suspect is because they often seemed to be followed with an alternative product they are trying to sell you. There are other oxidizing fungicides other than sodium hypochlorite (bleach) but they are not nearly as effective. Some companies use straight lye, also known as drain cleaner, on the shingles. The problem with alternative chemical solutions is they are often followed by pressure washing. In the picture is what I call the "surface cleaner on a rope". It is a neat looking tool but it carries its own risks.
First, this device is heavy. If the line used to feed it up and down the roof were to snap or break at sensitive couplers, the results could be disastrous to anything below. The second reality is that these types of surface cleaner require pressure to spin their spray bar. That means high pressure is running straight up and down your roof methodically taking those protective granules with it.
Which Roof Cleaning Method Is Correct?
Here is what shingle manufacturers recommend
The Asphalt Roofing Manufacturer's Association (ARMA) released a technical bulletin regarding the cleaning of asphalt shingles. A link to the full bulletin is posted in this article's reference links.
"Solutions for these ingredients may vary between shingle manufacturers
and depend on the amount of discoloration. Solutions range from one cup TSP, one gallon bleach and five
gallons of water, to one cup TSP and 2.5 gallons each of bleach and water."
There you have it direct from the horse's mouth. Also in the bulletin:
Caution!
High pressure washing systems for algae removal should not be used.
Just about every roofing contractor association and even owens Corning, one of the largest manufacturers of roofing shingles in the world recommends a low-pressure cleaning done with sodium hypochlorite... bleach. That's enough data for my company, PressurePros, Inc in Havertown, PA to assume this method is the correct one.
The Big Question About Roof Cleaning
Can I do this myself?
Over the years I have seen some very ambitious do-it-yourself projects that surprised the heck out of me in terms of workmanship and attention to detail. Can you perform your own roof cleaning. Of course. Just go into the task with your eyes open. On the plus side you may be able to save some money over hiring a contractor. On the con side are the risk for fall injury, possible chemical burns, and without enough manpower, the risk to your landscaping. Here are some tools you will need:
1. Ladder with roof saving "bullhorns" to reach the highest peak of your roof
2. Roof climbing safety gear including harness and anchor
3. If you are using household bleach, you will have to use it at nearly full strength. The average 3 bedroom two car garage home can easily eat over 50 gallons. (Plan on where you will dispose those plastic bottles.
4. A method to apply the cleaner. Pros use powered pumps such as pictured above. You can use a pump up or backpack sprayer. Do NOT use that sprayer for anything else.
5. A chemical filtering OSHA approved respirator
6. A method of catching runoff from gutters. You can wrap the draining end of your downspout in a trash bag.
7. A ground person to keep all vegetation constantly wet.
The Method For Cleaning
1. When you have attached your safety anchor and have your cleaning solution ready, you can begin wetting your landscaping. Keep in mind that rose bushes drink through their leaves so make certain everything is dripping wet. It is also a good idea to wet down your house. Dripping chemical can leave streaks that are nearly impossible to remove. Glass can also be etched.
2. Apply your chemical solution to your shingles. Shingles should be saturated just to the point where it begins running. The solution will turn white wherever there is growth. This is the oxidation process that will kill the Gloeocapsa Magma and any other mold spores. Lichen will turn white. Streaks that remain 15 minutes after application will need a second coating.
3. That's it. Let Mother Nature take her course. You will see improvement almost immediately. The next rainfall will remove any haziness and dilute the runoff to a safe level for your landscaping.
This is definitely on the high end of the risk factor scale for many reasons. By the time you buy your fall gear, ladder and cleaners and spend 6-8 hours on your roof, you may well have wished you hired a pro. that decision is yours to make. I want you to know exactly what you are getting into. PressurePros, inc assumes no liability in outlining the roof cleaning method above. you do so at your own risk.
Hiring A Roof Cleaning Contractor
When looking for a contractor it may not be in your best interest to shop with price in mind. Use this article as a guideline to asking questions. Check insurance and licensing requirements for your state. Make certain your contractor carries Workman's Compensation insurance as well. Talk to him or her about their methods, experience and attention to detail. Have them show you pictures of projects they have completed so you know what results to expect. With the right company you can expect a roof that looks new, your property value to increase and minimal to no damage to any of your landscaping. Certification is also a good sign that your contractor has been diligent in setting a standard for proffesional grade work.
Sources For This Article
OSHA Rules for proper fall protection
OSHA is a government agency that sets standards for safe workplaces and project sites.
OSHA standards for respirators
Learn which respirator is correct for being on a roof with cleaning chemicals
Wikipedia gloeocapsa magma
Read a detailed explanation and history of this cyanobacteria that causes those ugly black streaks.
Roof Cleaning Institute of America
A resource for contractor certification in roof cleaning. PressurePros, inc is a certified contractor
Asphalt Roof Manufacturers Association Technical Bulletin 217
The bulletin issued by ARMA regarding proper roof cleaning
Roof Cleaning PA
Providing roof cleaning services for the suburban areas surrounding Philadelphia, PA
Find the full article written by Ken Fenner here http://www.squidoo.com/roof-cleaning-removing-black-streaks
Provided for our Roof Cleaning customers in Little Rock AR
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