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Roofing/Roof Cleaning/Moss control


We have a composition roof that is about 7 years old. It is beginning to develop a pretty substantial moss buildup, so I am planning to have it cleaned in the spring, and probably have a moss treatment of some sort done.  

There are so many companies doing this, and such a wide range in pricing that it is very difficult to who to hire, and what would be a fair price.  I know that there are some scrupulousness contractors who claim to thoroughly clean and treat for moss, but actually do very little.  

Can you help with some suggestions about how to find the right company to do this work?  Also any guidelines for what would be a fair price.  Our home is small (1119 sq. ft), but has a couple of roof peaks and angles.  



Thanks for the question...moss is one of my least favorite topics!  The problem with moss removal is that always results in wear or damage to the roof surface.  Costs are going to vary based roof slope and accessibility on and around the residence, and intensity of moss build up.  Whether or not the contractor is going to adhere to OSHA fall protection requirements will also make a big difference in the cost.  So I am not able to suggest a 'fair' price for the work therefore obtaining several bids is the best avenue especially if you can define the scope for your contractors.

As for finding the right companies to do the work, I think you will have to do some homework on that. Be sure to check out whomever you choose with the construction contractors board and perhaps better business bureau.  Also, just being home, watching the work, and knowing what you are looking at will encourage any contractor to perform diligently.

Moss is sensitive to PH so the best environmentally responsible moss control products contain liquid acids or bases.  Both will have minor detrimental effects on your shingles, but less impact than another 7 years of moss growth.  St. Gabriel Organics Burn Out II in concentrate works nicely and is a mix of natural oils and citric acid.  Power washing should not be done, rather a stiff bristle broom should be used to remove heavier growth areas.  Treatments should be performed annually most likely, and best performed in the fall as the rainy season gets into swing.


Bruce Ryan II, RRO
Professional Roof Consultants, Inc.  


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Bruce A. Ryan II, RRO


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.


Bruce Ryan has 20 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.

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

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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