Proven Performance: Aged TPO Field Study

Abstract

New thermoplastic polyolefin (TPO) roof membranes have been extensively analyzed in laboratories, roof exposure farm fields, and under accelerated weathering conditions. The ASTM International material standard specification for TPO membranes has been regularly improved since its inception to incorporate more demanding tested-product performance, including requirements for accelerated weathering and aging. Industry data on the aged performance of TPO roof membranes to date has largely been based on laboratory work, regional studies, and anecdotal case studies of TPO roofs, predominantly those that have been improperly designed and/or installed, and membranes with retired formulations that resulted in premature failure. Today, there are TPO roofs in the United States that have been in service for nearly 20 years. This paper will review the long-term performance of a large sampling of TPO roof membranes installed throughout the United States by evaluating thickness, flexibility, inspection under 7X magnification, aged seam strength, and repair weld adhesion. The intent of this study was to evaluate 1) field-aged TPO roof membrane performance and 2) the ability to repair field-aged TPO roof membranes.

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