Exterior Insulation and Finish Systems (EIFS)

Exterior Insulation and Finish Systems (EIFS) are products for cladding exterior walls. These cladding systems integrate insulation with a stucco-like covering. However, EIFS differ from stucco in many respects. EIFS incorporate proprietary constituent components that have been developed and tested to be compatible and to fulfill specific building envelope performance requirements.

The fact that the term EIFS includes the word “system” is important to note. Proprietary EIFS rely on their components to interact and perform as a composite system. This is unique in comparison to most other cladding materials.

In addition to the ability to provide various forms and finishes, consider the performance capabilities offered by EIFS, and select systems from manufacturers that incorporate features that meet the project requirements. Considerations include fire safety, thermal resistance, resistance to rain penetration, interior air and moisture control, impact resistance, and other aspects of durability.

Some of the advantages associated with EIFS are:

  • EIFS can provide a continuous exterior layer of insulation for the building envelope. This can be designed to protect the building and backup wall structures from temperature extremes that promote undesirable thermal movements, and to protect against moisture damage from condensation. A continuous thermal barrier helps avoid thermal bridging and takes advantage of thermal mass (heat storage in the backup wall). This can improve energy performance, promoting savings in both the initial and operating costs related to heating and cooling equipment.
  • EIFS have a low weight (dead load) in comparison to masonry or concrete cladding. This can reduce structure costs, particularly where earthquake loads influence the design.
  • Properly applied and maintained EIFS provide good resistance to rain water penetration. The risk for rainwater penetration tends to be limited to joints, interfaces with other materials and where the lamina is damaged or otherwise defective. Most EIFS have a drained version of the system that should be used whenever the EIFS is likely to be wetted.
  • In comparison with rigid cladding systems, many EIFS are relatively flexible and better able to accommodate substrate flexure or other movements without cracking.
  • A wide range of finish colours and textures are available. Complex surface features are easily incorporated for distinct and interesting architectural facades.
  • Localized damage or defects in EIFS can be easily repaired. The appearance can usually be restored or renewed by reapplying the finish or by painting.
  • Lightweight EIFS can often be applied directly over existing cladding systems to: improve appearance;

Some limitations of EIFS are:

  • Some EIFS incorporate combustible components and/or combustible foam plastic insulation that must be protected as required by the applicable building code.
  • EIFS can be vulnerable to impact damage as a result of the relatively thin lamina. At areas where impact damage is likely, an appropriately reinforced EIFS product must be used.
  • Each EIFS constituent component and materials that connect to the EIFS must be compatible to assure acceptable performance. This includes the lamina, sealants, joint treatments, insulation, adhesive/fastening, moisture/air/vapour barriers and substrate. The manufacturer should be consulted to verify that each component and material has been tested to be compatible.
  • If exposed to frequent wetting, staining by mildew growth can result. Frequent wetting can occur where the EIFS are not effectively protected from rain, or in high-humidity climates where areas are not exposed to direct sunlight (north elevations, shaded areas, etc.).
  • As is the case with many multi-component, hand-applied systems, EIFS performance is sensitive to workmanship. Quality control is necessary to assure the various components are properly applied and that they effectively work together to provide the desired performance.
  • While a minimum 30-year service life for properly designed and applied EIFS is anticipated and indicated by field performance, longer term service for many product formulations has not been determined. As with all cladding, maintenance is a prerequisite to longevity. Problems with local deterioration or moisture ingress must be dealt with promptly to achieve an acceptable service life.

Figure 116

Components of an exterior insulation and finish system (EIFS)

Oncodes.ca publishes this information for educational purposes only (CMHC)