A New ASTM for Plaster Accessories
Since its formation in 2013, the ASTM C11 Stucco Work Group has worked toward reconciling inconsistencies in current standards and creating new standards that reinforce consistency in the stucco industry. The Stucco Work Group meets virtually via webinar and review items that have been proposed, make suggested changes and then develop those into ballot-worthy items for the ASTM committee to vote on a semi-annual basis.
As part of this activity, the Stucco Work Group helped develop a new ASTM standard for Plaster Accessories, reflecting more current industry practices.
The standard, ASTM C 1861: Standard Specification for Lathing and Furring Accessories, and Fasteners, for Interior and Exterior Portland Cement-Based Plaster, was approved for use by ASTM after the November, 2017 meeting of C11.
The standard is listed under C11.02, and is found in the ASTM book of standards, Volume: 04.01.
This specification contains the minimum requirements for lathing and furring accessories, fasteners, etc., as components of interior and exterior Portland cement-based plaster assemblies, used to facilitate lathing and furring installation (Specifications C1063, C1787), cement plaster application (Specification C926), and functionality of the completed stucco cladding assembly.
Because C1063 is a lathing installation standard and not a material specification, the objective of this new accessories standard is to specify the requirements of the prescriptive lathing and furring accessories and fasteners mentioned in ASTM C1063, and define their minimum standards on material types, gages/thickness and other characteristics. Lathing and furring accessory and fastener installation requirements remain in C1063 as well.
This standard does not replace ASTM C1063, but is a referenced standard within ASTM C1063 (as of the -18a edition) and serves as a more comprehensive view into the plaster accessories that can be used, or may be manufactured for today’s design and construction environment.
Highlights of the new data in ASTM C1861 include:
- Terminology: Section 3-revised definitions of Plastering Terms, to be relevant with today’s practices.
- Illustrations – Figure 1 illustrates multiple generic shapes and styles of accessories. These were included to provide basic guidance on the shape or appearance of the accessories; both old and new.
- Table 1 – Minimum Thickness of Lathing Accessory – expanded to cover aluminum and stainless alloys as well.
- Table 3 – Lathing and Accessory Fasteners – NEW table that relocates and updates the fastener specifications found in C1063; placing them in a concise, chart-format for easy reference.
- Section 4 – Lathing Accessories to Reduce Cracking – this new section includes revised definitions of Control Joints and Expansion Joints, making it much easier for Code interpretation.
This new standard will be useful to a wide spectrum of stakeholders, including building owners, specifiers, engineers, architects, manufacturers, and applicators throughout the industry. Looking forward, the SWG is now developing requirements that will fill the significant needs of building owners, designers, and craftsmen in the stucco industry for the use of continuous insulation and drainage, addressing other important stucco industry topics. I want to acknowledge Jeff Bowlsby CCS, CCCA, architect and stucco consultant with Simpson, Gumpertz & Heger Inc., who provided guidance as the committee fine-tuned the standard, via ASTM balloting process to make the new standard a reality.
The new standard is available and ready at astm.org/Standards/C1861.htm. ASTM documents are copy-written, so each copy can be purchased/downloaded/printed and it’s your “personal” copy. With a copyright, the document is not to be duplicated without ASTM permission.