IAPMO Board of Directors Upholds Continued Use of Gypsum and Concealed Building Spaces in Return Air Systems within the 2027 UMC
On February 6th, 2026 IAPMO’s Board of Directors (BOD) published their decision to deny two petitions submitted by Chris Ruch, Jeremy Zeedyk and David Vincent from Western States and SMART Local 104 related to the 2027 UMC. Based upon these actions, gypsum and concealed building spaces will be allowed for use in return air systems under the 2027 UMC.
In denying SMART’s petitions, IAPMO’s BOD upheld the previous decisions by IAPMO’s Standards Council to: 1) allow the continued use of gypsum and concealed building spaces in return air systems in the 2027 UMC; and 2) establish a Concealed Building Space and Independent Construction Task Group to address this issue in the 2030 code development cycle. Both SMACNA and ASHRAE appreciate these outcomes.
BACKGROUND / TIMELINE OF ISSUE
Chris Ruch from SMART Local 104 and Jeremy Zeedyk from Western States had advocated for an effective “ban on gypsum” during the 2027 UMC Technical Committee process in 2024-25. Despite opposition from licensed contractors, engineers and design professionals, the TC members agreed with Ruch and Zeedyk and voted to approve code changes for the 2027 UMC that would have effectively banned gypsum. In response to the actions of the TC, both SMACNA and ASHRAE appealed to the IAPMO Standards Council in September 2025. A hearing was conducted at IAPMO’s World Headquarters in Ontario on November 13, 2025. After reviewing the Administrative Record, listening to testimony and asking questions, the IAPMO Standards Council issued a decision to grant the appeals by SMACNA and ASHRAE on December 2, 2025 and thus overturned the 2027 UMC TC original code proposals.
SMART Local 104 and Western States then petitioned the full BOD on December 19, 2025 to overturn the Standards Council’s decisions. In their petitions, they claimed the IAPMO Standards Council did not follow proper procedures, did not rely upon evidence-based decision making, jeopardized IAPMO’s ANSI accreditation and otherwise created institutional harm and potential legal liability for the organization. A hearing was conducted at the IAPMO BOD meeting on January 22, 2026 to consider these extraordinary claims. On February 6, 2026 a decision was published by IAPMO’s BOD finding fault with each of Local 104’s claims and firmly rejected their petitions.
The procedural processes to “ban gypsum” have been exhausted for purposes of the 2027 UMC and the petitioners failed. CAL SMACNA is pleased with the result and thanks everybody who engaged in the process. Those interested in the issue, however, should be prepared to participate in the IAPMO 2030 UMC Technical Committee process and share their expertise with the Concealed Building Space and Independent Construction Task Group. In their final decision to deny Local 104’s petitions, The IAPMO BOD notes “it will be important for all experts in this space to participate in this task group to ensure a broad perspective is included.”
See copies of IAPMO BOD denial of Local 104’s petitions: