May 15, 2014

Two new nonmetallic plaster base standards have been approved by ASTM International Committee C11 on Gypsum and Related Building Materials and Systems.

Metallic and nonmetallic plaster bases, also known as lath, are used as reinforcement and to serve as an attachment mechanism for portland cement based plaster or stucco. While standards exist for metal lath, there had not been standards for their nonmetallic counterparts, which are generally made from materials such as fiberglass or plastic.

An increase in use of nonmetallic products, due to characteristics such as ease of use and non-rusting properties, has led to a need to develop standards. The standards are:

• ASTM C1787, Specification for Installation of Nonmetallic Plaster Bases (Lath) Used with Portland Cement-Based Plaster in Vertical Wall Applications - developed by Subcommittee C11.03 on Specifications for the Application of Gypsum and Other Products in Assemblies; and

• ASTM C1788, Specification for Nonmetallic Plaster Bases (Lath) Used with Portland Cement-Based Plaster in Vertical Wall Applications – developed by C11.02 on Specifications and Test Methods for Accessories and Related Products.

Bill Egan, manager, Engineering and Development, BASF Corp.–Wall Systems, and a C11 member, notes that ASTM C1787 provides minimum performance requirements when nonmetallic lath is used with stucco while ASTM C1788 lists minimum installation requirements for nonmetallic lath with stucco.

“It’s important to note that the new specifications are performance-based, meaning the product/system has to meet certain minimums that encourage innovation and product differentiation,” says Egan. ASTM C1787 and ASTM C1788 will be used by specifiers, test laboratories, contractors, manufacturers and regulatory groups. 

In addition to ASTM C1787 and ASTM C1788, C11 also developed one other nonmetallic plaster base standard, ASTM C1764, Test Methods for Nonmetallic Plaster Bases (Lath) Used with Portland Cement Based Plaster in Vertical Wall Applications, in 2012. The test methods in C1764 evaluate the performance of vertical wall applications of lath under a variety of test exposures, including performance under transverse load and vertical load.

All interested parties, particularly contractors, design professionals, consultants, code officials and manufacturers, are encouraged to join in the standards developing activities of C11.

To purchase ASTM standards, visit www.astm.org and search by the standard designation, or contact ASTM Customer Relations (phone: 877-909-ASTM; sales@astm.org). ASTM International welcomes participation in the development of its standards. For more information on becoming an ASTM member, visit www.astm.org/JOIN.

For more news in this sector, visit www.astm.org/sn-construction or follow us on Twitter @ASTMBuildings.

ASTM Committee C11 Next Meeting: Nov. 10-13, 2014, November Committee Week, New Orleans, La.
Technical Contact: Bill Egan, BASF Corp., Jacksonville, Fla., Phone: 904-996-6115; bill.egan@basf.com 
ASTM Staff Contact: Thomas O’Toole, Phone: 610-832-9739; totoole@astm.org 
ASTM PR Contact: Barbara Schindler, Phone: 610-832-9603; bschindl@astm.org

Release #9653