Thank you for your thoughtful input Mr. Gemek, I hope this information will help clear up how Gutterman view clean of roofs:

In response to my recent inquiry about cleaning roofs of algae, you indicated that you routinely power wash roofs.

I offer you the following article from the Asphalt Roofing Manufacturers Association which indicates that power washing should not be used. Other articles on the subject also indicate that power washing and harsh scrubbing with stiff brooms remove the fine particles on the shingles and reduce the useful life of the shingles.

I bring this to your attention because I have used Gutterman for years and would like to use your services for roof cleaning but I think your methods are incorrect in this case.

http://www.asphaltroofing.org/pdf/tb_217.pdf

AJ Germek

Thanks for your input Mr. Germek,

The term “power washing” is thrown around quite a bit to describe the application of water under pressure. Perhaps we should describe our process as “cleaning with non toxic detergents” and lightly using water to rinse the roofs. This may seem less invasive to some. To others the use of detergents like chlorine bleach and TSP that can kill black algae may sound too invasive, and certainly will harm plants, trees, and flowers when washed off the roof.

When we clean a roof ( case by case based on pitch of roof, degree of the stains, how safe it is etc.) we wash the roof by applying a citrus based biodegradable detergent. We wash it with our orbital washer with the pressure dialed down to about 700 psi vs. 2500 psi that most pressure washers are capable of. The roofs come out pretty clean. Each roof must be assessed on a case by case basis for the degree to which the treatment will be effective with out harm to the roof. Black Algae is a new phenomenon in NOVA, so we are all learning how to live and deal with it. I hope my explanation is helpful.

Herein is some information on the product we have found to be the most useful in roof cleaning.

Below is the orbital tool we use for “pressure washing” roofs:
		The application of zinc strips is also an effective remedy to keep the problem areas on roofs from getting out of control. Zinc is a natural predator of algae and water washing over the zinc strips washes down the roof and kills the algae spores.

Click here for more information on our cleaning product Limonene