Questions about EIFS overcladding
The original article also included some discussion of exterior insulation and finish system (EIFS) applications as an effective and frequently utilized approach for face-sealed overcladding to address aging or inadequately designed masonry facades. However, there is an interest in knowing whether there has been any skepticism or criticism of this approach among industry professionals, whether based on the technique or performance outcomes. The best answer is, there should be, depending on the particular EIFS product and application techniques utilized.
First developed and marketed in the 1970s, this once novel system has evolved quickly with greatly improved efficacy in more recent iterations. There continue to be some contractors and trades groups in the marketplace who may incorporate outdated systems and products in their solutions offered, but these must not be used for exterior overcladding of masonry in part because some of those systems provides no means for moisture management, including draining or drying of the system.
Teams considering using EIFS for a masonry overcladding application should refer to ANSI/EIMA 99-A-2017, Standard for Exterior Insulation and Finish Systems (EIFS) and EIFS with Drainage. According to the EIFS Industry Members Association (EIMA), the standard outlines “the generic materials, details, and design considerations for EIFS and EIFS with drainage,” noting that building professionals should consult manufacturer product literature for specifications, application instructions, and specific details. Thorough attention to the above will help avoid moisture penetrating through failed sealants or through cracks or flaws within the applied system and becoming trapped, creating deleterious conditions.
Water penetration must be mitigated with drainage and drying, and that is what newer EIFS systems are designed to do: drain and dry. This makes properly designed, applied, and assembled modern EIFS products highly effective as overcladding solutions for structural masonry. It is an adaptable approach that can succeed regardless of texture, joint design, and fenestration detailing, with benefits ranging from elimination of water penetration to enhanced wall R-value.
Building teams should keep in mind the success of this approach hinges on a sound masonry wall, parged smooth, and free of contaminants. As outlined in the ULC’s EIFS Standards, attempts to apply EIFS to masonry that is crumbling, spalling, loose, or cracked will likely result in system failure. Contractors and trades should consult the standards for all requirements of a successful application including dryness, temperature, substrate flatness and, perhaps most importantly, compatibility. It is important to note that combining elements of systems from different manufacturers can lead to unexpected and sometimes unsuccessful results.
Structural and budgetary questions and concerns
With respect to the solid masonry school buildings which are overcladded with face brick, the design solution and detailing typically includes creating
a brick shelf to support the face brick with modifications to the existing stone base. Above the first floor and grade level, where the new cladding must be attached directly to the existing backup wall, new relieving angles are attached to the load-bearing masonry wall to support the face brick. Note that structural engineers must verify the load-bearing capacity of the existing foundations and walls. Also, the design must consider the potential for the brick to expand, which can create tension and interactions with the attachment assembly.
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