The Fenestration and Glazing Industry Alliance (FGIA) and the Window & Door Manufacturers Association (WDMA) have jointly released the 2026 edition of AAMA/WDMA 100, introducing a significantly expanded industry standard for the installation of windows with mounting flanges in membrane drainage wall systems used in new construction.
The publication marks the first installation standard to be jointly issued by the two organizations, representing a major step in harmonizing installation guidance across the North American fenestration industry. The previous edition was published in 2012, and the new revision reflects more than a decade of advancements in building envelope technology, installation practices, and material compatibility.
AAMA/WDMA 100-26 broadens its scope beyond projects exposed to extreme wind and water conditions and now applies to all new construction applications. The updated document also expands coverage beyond traditional wood-frame construction to include additional wall assemblies. Among the most notable technical additions are recommendations for liquid-applied flashing systems at window jambs and heads, stronger guidance on material compatibility and system integration, and enhanced requirements for designing and installing interior air seals to improve overall building performance.
The standard provides installation methods specifically designed to manage incidental water infiltration by directing moisture from cladding joints, window assemblies, or perimeter installation gaps onto the membrane drainage plane, allowing it to safely exit the building envelope. 
Source: FGIA with additional information added by Glass Balkan
