2026 update expands scope beyond extreme conditions
The Fenestration and Glazing Industry Alliance (FGIA) and the Window & Door Manufacturers Association (WDMA) have published the 2026 edition of AAMA/WDMA 100, Standard Practice for the Installation of Windows with Mounting Flanges for Membrane Drainage Systems in New Construction Applications. According to Fenestration Review, the standard was last revised in 2012 and is now available for purchase through the online stores of both associations.
This publication is the first in a series of installation standards to be jointly published by the two organizations. It provides a consensus-based guide for installing windows with mounting flanges in membrane drainage wall systems used in new construction. The techniques in the standard are designed to allow incidental liquid water from superficial cracks in the cladding, window joinery or installation joints to drain onto the membrane drainage plane and exit to the building exterior.
A joint milestone for two associations
The publication marks a milestone in industry collaboration, according to the FGIA and WDMA. The 2026 edition is the first installation standard to be jointly published by the two organizations. The previous edition was last revised in 2012 by AAMA and FMA. The new standard reflects modern practices and consensus among manufacturers, suppliers, and installers in the fenestration and building materials sector.
What changed from the 2012 edition
When the standard was last revised in 2012, it focused on extreme wind and water exposure conditions. The 2026 edition extends the guidance to all new construction applications, including wood frame construction and other wall types. The addition of liquid-applied flashing recommendations at the jamb and head conditions addresses a common detail where water entry has occurred. The revised standard also includes more comprehensive guidance on interior air seal design and installation.
Key changes address flashing, materials and air seals
The new edition significantly expands the standard’s scope from extreme wind and water exposure conditions to all new construction applications. The scope now includes not only wood frame construction but other wall types as well, according to the FGIA and WDMA. Recommendations for using liquid applied flashing at the jamb and head conditions are included in this update. More robust material compatibility and system integration guidance was added, along with enhanced direction and explanation for the installation of an interior air seal.
“AAMA/WDMA 100-26 provides the fenestration and building materials industry with a modern, consensus-based installation standard for mounting flange windows in membrane drainage wall systems,” said Mike Liquindoli, product integrity manager for JELD-WEN, who serves as WDMA’s co-chair of the FGIA/WDMA Installation Committee. “This revision significantly expands the standard’s scope from extreme wind and water exposure conditions to all new construction applications, while also incorporating liquid-applied flashing methods, enhanced material compatibility requirements, and more comprehensive guidance on interior air seal design and installation.”
Water management drives long-term performance
The standard targets a common failure point in residential construction: water penetration around window flanges. The guidance is built around allowing incidental water to drain away from the rough opening rather than accumulate and cause damage. “Adherence to this installation standard ensures improved window performance and rough opening water management, as well as greater overall building envelope resilience,” said Lynn Miller, code compliance manager for MITER Brands, who serves as FGIA’s co-chair of the FGIA/WDMA Installation Committee. “These outcomes ultimately serve to provide truly meaningful benefits for our industry customers.”
Relevance for Canadian builders and specifiers
Flange-mounted window systems are widely used in Canadian low-rise residential construction, including wood-frame and mixed-wall assemblies common in Ontario and across the country. Builders and specifiers working under the National Building Code of Canada and CSA A440 can use the updated installation practices in AAMA/WDMA 100 as complementary guidance for managing water at window openings. The standard’s emphasis on membrane drainage and interior air seals aligns with the moisture management principles found in Canadian building practice.
The FGIA and WDMA note that the standard is referenced within the Florida Building Codes, and many manufacturers reference it as part of their products’ installation instructions. For Canadian window manufacturers and contractors, that reference status can influence installation documentation and warranty expectations, even when the local code does not explicitly cite AAMA/WDMA 100.
Material compatibility and system integration
The standard now includes more robust material compatibility and system integration guidance, according to the FGIA and WDMA. This helps installers avoid incompatibilities between sealants, flashing tapes and window components that can lead to premature failure. The interior air seal direction is also enhanced, providing clearer explanation for installing an air seal that limits air leakage and moisture movement at the window perimeter.
Availability and industry adoption
The 2026 edition is available for purchase from the online stores of both FGIA and WDMA. The update reflects industry collaboration and modern practices, according to the two associations. The standard’s expansion to all new construction applications, rather than only extreme conditions, makes it relevant to a broader range of projects, from single-family homes to low-rise multi-unit buildings.
For glazing contractors and builders, adopting the guidance can reduce callbacks and water-related warranty claims. The FGIA and WDMA state that adherence to the standard leads to better construction practices and improved long-term performance of window installations. The standard’s clear direction on liquid-applied flashing and interior air seals provides installers with practical details that have often been missing from manufacturer instructions. For Canadian window fabricators and installers, the expanded scope means the standard can be applied to typical production housing, not just coastal or high-wind zones.