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Roofing/Dark Streaks on Roof

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Expert: Bruce A. Ryan II, RRO - 11/11/2009


Question
My roof has dark or even black streaks over most of it running vertically.  What can I use to remove them without damaging the shingles.  The house is approximately 20 years old. The roof is typical roofing shingles used in the south.  I assume some type of tar or fiberglass combination.  My yard is full of large oak trees, red oak, white oak,some maples and hickory.  Any suggestions would be appreciated.

Don Webb

Answer
Don,

The black streaking is usually caused by an algae that thrives on the limestone fillers within the asphalt shingles.  Try cleaning your roof (or having a contractor clean it) using an oxygenated bleach product.  Try the link (cut and paste into your browser)for stain solver or use a similar product.  I am unsure how much you will need, nor do I endorse or guarantee a product.  

http://www.stainsolver.com/Why_Use_Stain_Solver.shtml

Be mindful that the algae is really not harmful to your shingles so doing nothing is also acceptable.

Regards,

Bruce Ryan, RRO
Professional Roof Consultants, Inc.

Roofing

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Bruce A. Ryan II, RRO

Expertise

I offer solid knowlege of all types of Commercial and Residential Roofing, Waterproofing, and, Building Envelope systems. Experience ranges across low slope and steep slope roof systems. I am also well versed in matters regarding condensation and ventilation. I enjoy donating some of my time and knowledge to the betterment of others.

Experience

Bruce Ryan has 13 years of roofing, waterproofing, and building envelope consulting experience with PRC, with 5 years of commercial roofing experience prior to joining the firm. He became Vice President of the company in 1998. Bruce Ryan plays a key role in the development of practical, long-term roofing and waterproofing solutions, along with implementation of on-site forensic studies. Bruce also has a high level of experience with regard to the impacts of roofing materials and construction for demanding clients with heavily occupied structures.

Organizations
Oregon Construction Contractors Board Construction Specifiers Institute National Roofing Contractors Association The Institute of Roofing, Waterproofing, & Building Envelope Professionals Oregon Board of Investigators Installation Masters

Education/Credentials
University of Maryland BS Business & Administration Registered Roof Observer - RCI Private Investigator Certified EIFS inspector - Northwest Wall and Ceiling Bureau Certified InstallationMaster™ - The Installation Masters™ Training and Certification Program (developed by American Architectural Manufacturers Association)

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