This specification covers the minimum requirements, improved methods and best practices for reducing cracking in exterior and interior portland cement-based plaster, as referenced in Specifications C1063 and C926. These requirements do not by default define a unit of work or assign responsibility for contractual purposes, which is the purview of a contract or contracts made between contracting entities.
Keywordscontrol joint; expansion joint; lath; portland cement-based plaster; crack reduction
Proposed new industry standard as minimum requirements to address industry concerns about reducing cracking of stucco wall claddings, the use of control joints and to recognize and encourage the use of multiple various crack reduction methods. Some crack reduction methods are lathing specific, others plastering specific, so the proposed new standard proposes changes that apply to both C1063 and C926. This approach considers the effectiveness of all crack reduction methods collectively. Certain conditions such as gapped plywood and OSB sheathing panels, and moist curing of plaster are basic minimum requirements that apply to all crack reduction methods, are not considered as variables and therefore are not given special recognition. Once this new standard is approved, C1063 and C926 will be revised to reference it as a minimum requirement.
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development