Exterior insulation finish systems (EIFS) outperformed brick, stucco, and cementitious fiberboard siding in U.S. Department of Energy (DOE) tests measuring energy efficiency, moisture intrusion, and temperature control in identical, side-by-side field installations. 

Based on the study, EIFS (including EIFS with drainage) is the exterior cladding of choice for achieving the key building performance goals of energy efficiency, temperature and moisture control in mixed, coastal Zone 3 climates. 

The DOE, through the Office of Energy Efficiency and Renewable Energy's Building Technologies Program, and the EIFS Industry Members Association (EIMA), sponsored the study conducted by researchers at the Oak Ridge National Laboratory (ORNL).

The testing was done on a building constructed near Charleston, S.C., that features exterior wall panels made from the various claddings and assemblies.  Each panel is fitted with an array of sensors that provide a full profile of temperature, heat flux, relativity humidity, and moisture content values.  The data was collected 24 hours a day and transmitted back to the ORNL research facility located in Oak Ridge, Tenn., where the data was extensively analyzed.

Key Findings Illustrate EIFS Advantages

Key findings of the study gathered by ORNL researchers between January 2005 and June 2007 include:

  • EIFS with four inches of foam outside the stud cavity, a liquid applied water-resistive barrier coating and no insulation in the stud cavity was the best performing wall configuration.
  • EIFS absorb little moisture and maintain a consistent, acceptable moisture level within the cladding despite varying outdoor conditions.
  • EIFS with drainage and a liquid applied water-resistive barrier coating readily disperse liquid water and moisture introduced by flaws in the building envelope.
  • Liquid applied water-resistive barrier coatings outperform sheet goods.  In addition, EIFS with water-resistive barrier coatings performed significantly better than other claddings that used building paper or spun-bonded polyolefin membranes.
In the testing, EIFS drainage layers comprised of vertical ribbons of adhesive and a liquid applied water-resistive barrier provided the most effective method for managing bulk water intrusion into the cladding cavity.