Exterior Insulation and Finish Systems (EIFS) consist of a foam insulation board, an adhesive and/or mechanical attachment of the insulation board to a substrate, a base coat on the face of the insulation with a glass fiber reinforcing mesh embedded in it, and a textured, protective finishing coat. Prior to the installation of the foam insulation board, a water-resistive barrier is placed on the substrate's surface. These components, applied according to the application protocols established by each EIFS manufacturer for each of the manufacturer's respective systems, comprise EIFS.

 

All the construction materials that are a part of EIFS have been manufactured by suppliers who are approved respectively by each EIFS manufacturer.

 

Exterior Insulation and Finish Systems are tested for durability and fire resistance as a unit using the specific construction materials from approved suppliers of the components. These systems have been tested for their ability to effectively resist fire, as required by all U.S. model building codes, successfully passing required tests and exhibiting desired performance in actual fires. To ensure performance, installed EIFS must be comprised of the same components to that tested.

 

Sometimes EIFS assemblies are installed using untested materials and practices. Unfortunately, many untested materials that are a part of the system and are intended to resemble EIFS cannot be readily distinguished by observation from fire-tested, code-compliant EIFS systems. Such configurations and/or materials, if tested properly, may fail to meet building code requirements. This is true of EIFS application practices, too.

 

Why might the use of untested, non-code complying materials increase the risk of fire? To illustrate, EPS insulation used in noncombustible construction is traditionally attached to a gypsum board or concrete/masonry substrate. In a fire, these substrates act as a heat sink slowing the temperature increase and delaying ignition. When the traditional EIFS substrate is removed, ignition of the EPS can occur more quickly and may result in flame propagation. The base coat and reinforcing mesh have been shown to resist flame spread and also help to retard ignition by forming a protective barrier over the EPS. Substituting untested coatings such as polyurethane or polyurea for traditional EIFS base coat and finish has been shown to increase the flammability of these applications in a fire. Any modification to a tested and approved design, such as the use of polyurethane based coating or trim accessories at the heads of wall penetrations and at horizontal terminations (expansion joints) should only be undertaken after the appropriate fire test(s) have been conducted to verify no adverse affects on fire performance.

 

The type of insulation board used in an EIFS application can also have an impact on the product's performance in a fire. For example, employing a foam plastic other than a traditional EPS board could lower resistance to a fire. Regardless of the type of foam insulation installed, it should never exceed the maximum thickness allowed, and it should be identical to that used in the system that was fire tested (or listed in the manufacturer's current evaluation reports).

 

To avoid the potential for unsatisfactory performance in a fire, architects and contractors who specify and install EIFS should employ only fire-tested, code approved full EIFS on their projects.

 

For further information, please contact EIMA's office at 1-800-294-3462.