Forensic Engineering Comparison of Two Masonry Cladding Systems

Abstract

In a recent construction litigation case, there was a disagreement between two qualified engineering experts regarding the technical requirements of a masonry veneer cladding system that was installed on the exterior walls of a residential structure. The disagreement among the experts was related to the classification and function of the veneer cladding system. Specifically, the classification of the cladding system as cast stone or adhered masonry veneer directly impacted the functional requirements set forth by applicable codes and standards. Depending on this classification, the veneer system may or may not be subject to various aspects of the building code, industry standards, and code evaluation reports. The primary areas of concern included the attachment of the panels (i.e., anchored vs. adhered) to the masonry substrate, the extent of water intrusion, and the need for water management details (i.e., flashing and weep holes). Both expert witnesses relied on applicable building codes, industry standards, and manufacturer literature to form their opinions to a “reasonable degree of engineering certainty,” yet these technical differences remained. This paper presents the technical highlights of this case study and identifies the issues where building codes and applicable standards require further clarification.