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Continuing Education Use the following learning objectives to focus your study while reading this month’s ARCHITECTURAL RECORD / AIA Continuing Education article. Learning Objective: After reading this article, you will be able to: 1. Compare traditional EIFS to EIFS/the next generation. 2. Describe the main drawback of EIFS/with traditional moisture protection. 3. Identify construction detailing to avoid water intrusion problems in EIFS.

Traditional EIFS

A traditional EIFS (Figure 1) is a non-load bearing cladding and consists of five components: an insulation board, an adhesive and/or mechanical fastener to attach the insulation board to a substrate, reinforcing mesh for impact resistance, a base coat to embed the reinforcing mesh and to provide weather resistance, and a decorative and protective finish coat. This is the most popular type of EIFS and is classified as a Class PB (polymer based) System by EIMA. It is lightweight, easily accommodates aesthetic features such as decorative trim and reveals, and, in general, it does not require expansion and control joints like conventional stucco or masonry veneer. Its main limitations are impact resistance, and it is a barrier, or face seal wall design, which, in tandem with other barrier components—windows and sealants—resists water penetration at its outer surface.

 

Figure 1. A Class PB EIFS consists of five components: adhesive, insulation board, base coat, reinforcing mesh and finish coat. Together they function as a decorative and protective insulating wall covering.

EIFS and Building Codes

While EIFS have been in use in the United States for more than 30 years, they are not explicitly covered in model building codes. For materials or methods of construction that are not covered, building codes generally permit the use of alternates by providing the building code official with the authority to approve alternates with justification such as testing, engineering analysis, or some other evidence of compliance with the intent of the code. Such approval is generally granted on the basis of evaluation reports written by model code evaluation services. The evaluation report establishes the method in which a system or product is to be used, limitations associated with its use, and that it is an equivalent to the construction materials/methods of the code. The evaluation report should always be consulted when considering EIFS as the exterior wall covering, as it not only provides a means to verify compliance with the applicable code, but it is also evidence that the product has been thoroughly tested and evaluated.

To obtain an evaluation report manufacturers must satisfy numerous criteria published by evaluation services that verify system durability, structural and fire performance, as well as compliance with quality control programs. The use of foam plastic insulation in wall construction, in particular, requires extensive testing to verify performance. The IBC2 presents the most comprehensive set of requirements, as it essentially merges the requirements of other model codes into one book. The basic requirements for the use of foam plastic in walls are established in Chapter 26. This includes:

• Labeling
• Separation from the interior.
• Fire performance testing (see Tables 1D and 1E in this article)

Figure 2. The photo illustrates testing in accordance with UBC Standard 26-9. The test replicates a two story structure with a fire in an interior compartment and examines lateral and vertical flame spread. The test is one of many criteria set forth in model codes to evaluate the performance of foam plastic-based wall assemblies. It is one of a series of fire tests that qualifies EIFS for use on buildings of noncombustible construction.