The Expanded Metal Lath Association of the National Association of Architectural Metal Manufacturers announced the completion of a comprehensive testing program to determine the minimum acceptable load capacities for expanded metal lath under transverse loading with traditional 3-coat stucco wall systems. The third-party test results proved these types of wall systems perform exceptionally well in high-wind zone environments.

The stucco tests were performed in August 2011 at Smith-Emery Laboratories in Los Angeles, CA, in conformance with the International Code Council’s acceptance criteria AC 191 -Acceptance Criteria for Metal Plaster Bases (Lath).  The lath plaster was installed in accordance with ASTM C1063 - Standard Specification for Installation of Lathing and Furring to Receive Interior and Exterior Portland Cement-Based Plaster and ASTM C926 - Standard Specification for Application of Portland Cement-Based Plaster.

 With a general lack of industry published data or research for stucco systems, EMLA conducted this “first ever” industry association testing on common metal lath and stucco assemblies to provide baseline load data to design professionals, end-users, and standard organizations. A summary of the test results and the test program are available at