What's with
my Black-Streaked Shingles?
I am sure that many Laurel Branch residents like me have seen and/or experienced the black-streaked
roofs visible throughout our neighborhood. I am sure that like me you may have wondered what the stains
are, where they come from, and how to get rid of them. Well I went online and consulted the Ask
the Builder site found at http://www.askthebuilder.com/ and was able to get most of the following information. Other information was gathered via the internet
and from the Roof Center Store.
So, what is it? Roof staining was associated
with mildew in years past.
Mildew is a by-product of fungi. “
However, it has been determined
that another organism has invaded millions of newer asphalt shingle roofs around the USA. This organism is an algae, Gloeocapsa
magma. It has experienced an explosive growth curve during the past 15 to 20 years quite by
accident”. The accident? Years
ago algae didn’t grow on asphalt roof shingles because they didn’t have a food source. That
all changed when fiberglass shingles were introduced within the past 20 years. These fiberglass shingles
made today include large quantities of limestone on which this algae thrives. Limestone was introduced to increase the weight
of the new fiberglass shingles.
So, how do I get rid of the algae? Between Ask the Builder, other on-line sources, and our local Roof Center Store in White Plains
I have gathered this information. It is widely recommended that the algae be eliminated by use of a spray
developed specifically for that purpose. Definitely not chlorine bleach
or power washing. There are a number of products offered on-line and two that I am familiar with that
can be purchased locally. These two products are Shingle Shield Roof & Deck cleaner (can
be purchased at the Roof Center) and Spray & Forget Roof Cleaner (can be purchased at Bryans Road Supply) and are typically distributed in 1 gallon containers. These
products are mixed with water and applied with a garden sprayer type of sprayer. These products claim to
be safe for your plants but it is a good practice to hose your plants down before and after the application of the product.
How quickly you will see results will generally depend on how bad the stains are and the ratio of the product to water
mix you use. It may take as long as three months for total stain removal but should not require another
application.
Ok, so it’s gone. How do I keep it from coming back?
All the information I have gotten so far has said the best way to prevent
the occurrence or reoccurrence of the algae is by use of copper or galvanized (zinc), not aluminum, flashings or strips attached
near the peak of the roof. These metals it is said give off enough metallic particles when it rains to
prevent the growth of algae. Shingle Shield Zinc Strips are available at the Roof
Center. Installation instructions are available through the manufacturer.
That’s all well and good but I can’t or won’t
get on my roof. Who will? Good for you!
Roofs are tricky business and are very dangerous. It is my understanding that most roofing contractors
will do this kind of work. Just protect yourself by contracting with a licensed,
bonded, and insured contractor.
I’m going up anyway what do you say
to that? If you do you should realize that how high you go,
the slope of the roof, and working with awkward (the sprayer) items and wet surfaces contribute to your amount of risk.
At the very least you should invest in a fall arrestor system. OSHA approved fall arrestor systems
(available at The Roof Center Store or Lowe’s) consisting of a full body harness,
lanyard, safety rope, and roof anchor brackets are available for around $130.00.
Are you recommending/endorsing the products
and vendors mentioned in this article?
Not
at all. I used them as a source of information only. Neither the LBHOA
nor I make any recommendation or endorsement of any vendor, product, or web site identified in this article.
