Knowledge Center

If you’re reading this, you more than likely have some ugly black stains on the roof of your home or business. If you don’t find the answer here and would like to send us a question by email, we will do our best to answer your questions.

What is it?

As you know by now if have read the information on the “about” page of this website, the black stains are caused by a “roof algae” for lack of a better term. Technically it belongs to a classification of single celled bacteria. This algae finds a source of nutrition on the limestone minerals found in modern asphaltic-fiberglass shingles. As long as the algae has the right conditions, it will thrive and propagate by what is called Binary Fission. That means that each single celled Gloeocapsa Magma develops a new “cell wall” that divides it in half, then it splits into two cells . Each cell, as long as it has the right conditions, follows suit. The progression is 1 cell to 2, 2 to 4, 4 to 8, 8 to 16, 16 to 32, ... etc. You can easily see with this type of progression why the black stains seem to worsen rapidly once they establish themselves on your roof!

Click this link (not yet active) for a more detailed description of the scientific nomenclature and technical information on Gloeocapsa Magma.

What will it do to my roof?

The black stains on the roof are damaging to the roof mainly by making the shingles darker and producing more heat via solar energy conversion. They seal the shingle surface with a smooth (and VERY slippery when wet) coating as the colonies spread down the roof (assisted by gravity). You’ll notice that the stains typically enlarge in width as they spread down the roof. This is an example of the geometric progression of cell division assisted by gravity in a downhill slope condition.

We have found that on cleaning the roof with black algae stains, that the underlying shingles are in remarkably good condition ... unless... (this a big unless) there is lichen or moss growth that has started. These are the destructive organisms to any shingled roof surface. Lichens and moss have been breaking down rocks for millions of years... shingles are easy prey!

The progression is the spread of algae, followed by lichen, and/or moss growth. The algae acts a nutrient source for both the Lichens and moss. Getting rid of the algae before the subsequent two possible growth stages will insure the longest lasting performance of your roof.

Your roof will look like new, for roughly 10% of the cost of installing a new roof. Increasing market value, appearance, and long term savings are but a few of the benefits. Cleaning and maintaining an algae free roof can realistically add ten to 15 years of useful life to your shingled roof.

Click on this link (not yet active) for more detailed and scientific information on lichens and moss.

How do you clean it?

We use a non-toxic biodegradable product to clean your roof. If you look at all of the other websites that market roof cleaning services and roof cleaning products, they will have a private label on their “green, biodegradable, revolutionary” new product. Others call their chemical formulations “proprietary” (a trade secret). What they won’t tell you (and we will) is that we (and they) are using the same ingredient... sodium percarbonate.

Sodium percarbonate is a powdered concentrate that when mixed with water produces Hydrogen Peroxide...the same thing you have in your medicine cabinet in a brown bottle. So...is it safe? Yes. In lower concentrations it is used for mouthwash, tooth whiteners, antiseptic applications etc. Hydrogen peroxide has the unique capacity to permeate organic materials and “blow them up” from the inside out with it’s powers of oxidation, yet has no effect on inorganic materials. That’s exactly what it does to the roof algae, with a foaming action that is like the action when you disinfect a cut. The late Billy Mays is responsible for selling more Sodium Percarbonate than anyone in the world… it is 40% of the ingredients in Oxy-Clean. (the balance is detergents, perfume agents, and fillers)

Pure Sodium Percarbonate can be likened to oxy-clean on steroids.

The Asphalt Roofing Manufacturer’s Association is currently recommending a mix of tri-sodium–Phosphate and Chlorine bleach to treat algae stains. Not only is the currently recommended method not as effective, it is environmentally irresponsible and even damaging to the shingles! We have sent them a letter requesting a review and revision to their recommendation, but to date have had no response. We’ll keep you posted on that one!

Once the sodium percarbonate solution has killed the algae (within 1/2 an hour or so) we use a low pressure (300 to 350 psi) wash to dislodge the dead algae residue from the shingles.

Hand under powerwasher

Click this link (not yet active) for a more technical description of the hydrogen peroxide reaction on a cellular level.

How long will the cleaning last?

Typically your roof will be algae/lichen free for two to 3 years after cleaning. After two years, we recommend an application of Sodium Percarbonate solution to your roof as a preventative measure. Individual conditions may vary based on house location.

All of our client information is entered into a database (absolute privacy assured) and the are sent a follow-up reminder in two years to give them the opportunity to have us perform this preventative service. The cost of doing this is a fraction of the initial roof cleaning price.