ENVELOPE SYSTEMS/EIFS
Design and Construction Issues
There are several design and construction issues relevant to the performance of EIFS. As with
other construction systems, it is important to follow the installation requirements of the EIFS
manufacturer. These systems are sensitive to poor application and require careful construction
technique, especially at joints and penetrations. One issue of construction technique is the
application of a sufficient thickness of base coat. The base coat thickness, coupled with proper
embedding of the mesh, is critical for the system's durability in terms of impact and water
resistance. A minimum thickness of about 1.6 mm (1/16 inch) is recommended by many
manufacturers, while others recommend a minimum thickness of 2.4 mm (3/32 inch).
Bordenaro points out that some performance problems in EIFS cladding systems are due to the fact
that since they are among the last components of a building to be applied they are often shorted in
the number of detailed drawings that are developed relevant to their application. Drawings are
sometimes not provided to show how the EIFS cladding will relate to other products and finishes
such as doors, windows and other penetrations. Many manufacturers have standard details for
large penetrations such as windows and doors, and these need to be followed. However, details for
other small and common penetrations, such as at conduits, are generally not available. Continuity
of the insulation and air barrier systems must be purposefully addressed at each component
connection over the entire building envelope. Details must be developed for each such connection,
otherwise this continuity will break down and the overall system performance will suffer.
References
Bordenaro, M., "Tricks of the EIFS Trade", Building Design & Construction, January 1991
Exterior Insulation Manufacturers Association, Guideline Specifications for Exterior Insulation and Finish
Systems, various dates of publication.
Labs, K., "Inside EIF Systems," Progressive Architecture, October 1989.
Piper, R., `Troubles with Synthetic Stucco," New England Builder, June 1988.
Williams, M.F. and Williams, B.L., "Sealant Usage for Exterior Insulation & Finish Systems," Building
Sealants: Materials. Properties. and Performance, ASTM STP 1069, Thomas F. O'Connor, editor, American
Society for Testing and Materials, Philadelphia, 1990.
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