text: Those ugly, dark streaks on an asphalt shingle roof are
  not a defect in the shingles or a sign of a bad
  shingling job. It's algae that causes the roof to look
  bad. Some experts say algae may cause shingles to
  deteriorate prematurely.
  
  This type of hardy, blue-green algae (Gloeacapsa magma)
  thrives in warm, humid climates. In the Midwest, it
  normally appears on a north slope where shade and
  moisture support its growth.. However, the problem is
  most severe in the southeast Gulf states, where entire
  roofs can be covered in as little as four years.
  
  The algae feed on inorganic filler materials such as
  calcium carbonate in asphalt shingles.
  The Family Handyman Magazine, May 2004
  
  What is the Solution?
  
  1. Well,
  you could ignore the problem. But if you do, the
  moss, mold and algae will eventually destroy your roof.
  
  2. You
  could get a new roof if you would like to spend between
  $4,000 and $10,000+.
  
  3. Or you
  could take charge and put an end to the problem. Fungus
  should first be removed by washing with a non-hazardous
  chemical treatment.
  
  THAT'S WHERE WE COME IN!
  
  Duffyʼs Dirt-be-Gone Pressure and Soft Wash can help you
  with all your exterior needs -- from soft washing your
  roof to pressure washing your siding. We are
  licensed and insured and care about doing a quality
  job. We offer free estimates and friendly,
  personable service.
  We
  work
  in
  residential
  and
  commercial
  communities;and
  offer competitive prices.
  
  Call us
  today! 757-289-8343
  
  We specialize in
  Soft Wash Roof Cleaning!
  
  Did You Know?
  
  1.
  Moss can break down fibers in shingles, forcing them apart
  and allowing leaks.
  
  2. Fungus reduces the ability of the roof to reflect
  away light and heat, making for higher air conditioning
  bills.
  
  3. A roof covered in fungus detracts from the
  appearance of the whole house, since the roof is one of
  the largest visible surfaces
  
  4. Many roofs are replaced prematurely due to damage
  by neglected moss
  
  Mention our website
  and get 10% off your service!Discounts available for
  churches, seniors, and military!