SYMPOSIA PAPER Published: 01 January 1996

The Effect of Base Coat Thickness on the Water Resistance of Class PB (Polymer Based) Exterior Insulation and Finish Systems (EIFS)


The water resistance of the base coat in exterior insulation and finish systems (EIFS) is critical for overall system performance. ASTM E 331 is used to investigate the water resistance of PB EIFS specimens which incorporate different base coat thicknesses. Test results for specimens with and without finish coat are presented. It was found that PB EIFS base coats in full compliance with recommended application requirements did not allow water intrusion at the industry-specified test pressure of 299 Pa (6.24 lbf/ft2). Based on these test results, observations on the typical failure mode of specimens which allowed water intrusion are presented, and the implications of test results are discussed.

Author Information

Williams, MF
Williams Building Diagnostics Inc., Maple Glen, PA
Williams, BL
Williams Building Diagnostics Inc., Maple Glen, PA
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Developed by Committee: E06
Pages: 103–114
DOI: 10.1520/STP39215S
ISBN-EB: 978-0-8031-5561-9
ISBN-13: 978-0-8031-2040-2