Single Ply roof membranes have been in extensive use inthe Northeast Region of the United States for a period of over twelve years. Although numerous systems and application procedures have been employed there has been limited publication of field performance data on in-situ systems. This study involves the review of both EPDM roof membranes and PVC roof membrane systems that were placed in service between 1977 and 1984. The roof systems included in the study are all reroofing systems of known construction, contractors, materials manufacturers and design. The performance study included a review of the documented history of each roof from design through construction and post construction. Warranty claims, if applicable, were reviewed as well as all other available recorded data.

Building occupants/Owners were interviewed to provide additional undocumented data. All roof systems in the study were inspected to establish existing conditions and to evaluate the level of deterioration of the various roof system components.

Accumulated data from documented history, interviews and field observations will be analyzed in this paper and defects will be summarized. Causation of defects and deterioration were also considered and classified into one or more of the catagories of design defficiency, material performance, improper workmanship and/or lack of appropriate and regular maintenance.

Conclusions relative to the performance of the systems studied will be presented and considerations given to the effect on performance by known system changes.