SYMPOSIA PAPER Published: 01 January 1987

Observations on Atmospheric Corrosion Made of Architectural Copper Work at Yale University


A six-year study of roofing and flashing of various buildings including many at Yale University was conducted. The buildings had architectural copper, which was in service for up to 100 years or more. There was great variety of usages. Various components had failed while others were salvageable and still others only slightly worn. Because of the varying degree of wear we attempted to find the reasons for this degradation. Methods of installation, location, orientation, and other factors were evaluated. Samples were taken, measured, and photographed. Some samples surfaced with lead faired better than some with no coatings. Lead coated copper on vertical surfaces did not wear as rapidly as on flat surfaces. Contaminants in the atmosphere appeared to increase rates of corrosion. Asphaltic or aluminum bearing repair materials produced adverse affects and were ineffective in stopping the leaks. Lead coating and patina were important in reducing the rate of aging. Size and method of restraint were also important. Large panels were subject to fatigue and cracking. Pitting at soldered seams was frequently observed. Photographs depict various sequences. Formation of patinas in corrosion products were observed. Lead coated copper was found to turn green after approximately 25 to 35 years of exposure on horizontal surfaces. Vertical surfaces remained grey or white. Reduction of serviceability depended more on method of installation, detailing, and design, than on the corrosion-induced deterioration.

Author Information

Fishman, HB
H. B. Fishman & Co., Inc., South Windsor, CT
Darling, BP
H. B. Fishman & Co., Inc., South Windsor, CT
Wooten, JR
H. B. Fishman & Co., Inc., South Windsor, CT
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Developed by Committee: G01
Pages: 96–114
DOI: 10.1520/STP25843S
ISBN-EB: 978-0-8031-5023-2
ISBN-13: 978-0-8031-0966-7