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Roofing/Animal damage to roof membrane


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We have some damage to a rubber membrane roof used in a transition area between a home and attached garage.  It looks like an animal has been scratching at the areas where there was a metal fastener under the membrane.  Alternatively, the membrane may have degraded in those areas and subsequently attracted squirrels or some other animal trying to get at insects that were trapped in the membrane hole.  Are those metal fasteners a problem area for a rubber roof substrate?  Do you have any experience or advice with this type of problem?  Thanks for your help.


We find that birds (large ones like seagulls) will sometimes become fascinated with whatever they think is under the membrane and they will peck holes in it.  They generally do not focus on fasteners specifically, and I have only seen it with polyisocyanurate insulation underneath the membrane.  It does not appear that your problem started with the birds however, but you definitely have a critter working at the holes now.

While the metal fasteners are perfectly acceptable to the manufacturers when positioned directly under the membrane, I will suggest that frequently as the roof ages the fasteners can protrude through the membrane.  Perhaps the foot traffic from the last roof replacement had something to do with it?  

The membrane appears to be quite old and at this point you should consider replacing it if that is in fact the case.  Otherwise, engage a roofing contractor that is skilled in EPDM roofing for a proper repair so that that area of high water concentration does not leak.  To prevent this issue in the future, consider having an overlay board fully adhered over the mechanical fasteners to separate them from the membrane.


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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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