ASTM WK73494

    Revision of C926 - 20 Standard Specification for Application of Portland Cement-Based Plaster

    (What is a Work Item?)

    Active Standard: C926 - 20b

    Developed by Subcommittee: C11.03 | Committee C11 | Contact Staff Manager



    bond; brown coat; cementitious; exterior plaster; fog coat; portland cement; scratch coat; stucco;;


    As discussed and reviewed for ballot by the Stucco Work Group Rationale: 1.Since the Annex of ASTM C926 is now being considered as an integral part of the main code, this item is a part of a review of the items in A.2 Design Requirements (previously called Design Considerations.) as to the feasibility of each Paragraph being in concert with the intent of the code. 2. Section 101.3 of the 2018 International Building Code states: The purpose of this code is to establish the MINIMUM REQUIREMENTS 3. A further consideration is that Plaster comes in a myriad of variations and is not just a single, homogeneous system. This revision is specific to residential style nail-flanged windows and doors. Other plaster system may need j-mold and caulking at the plaster-to-window frame juncture. 4. For this Item A2.1.3, the wording is vague, overly general and misleading. Three coat exterior plaster is designed as a water managed system where the water barrier is the Water-Resistive Barrier (WRB) behind the plaster body. All caulking and sealing for water control is done at the WRB level and not a the surface of the plaster. 5. Two coat systems over solid bases (such as concrete block or concrete) are considered barrier walls and a WRB is not required. Here is where the sealing and caulking, if required by the contract documents, must be done a the front of the plaster.

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    Work Item Status

    Date Initiated:

    Technical Contact:
    Matthew Innocenzi

    Draft Under Development