Government Study: EIFS Is “Best Performing Wall System”
SUMMARY: Oak Ridge National Labs states that EIFS are “best performing wall systems.”
New research comparing both overall insulating ability and moisture resistance show EIFS with 4-inch foam insulation "outperformed"
walls of brick, stucco, concrete block and cementious fiber board in moisture handling with "superior thermal performance."
ATLANTA, Oct. 28, 2006 — EIFS “outperformed all other walls in terms of moisture while maintaining superior
thermal performance."
That’s what the Oak Ridge National Laboratory said about walls made of EIFS, comparing them favorably to other
common types of wall construction based on 15 months of new research.
The government research initiative scientifically recorded the performance of EIFS – Exterior Insulation and
Finish Systems – with walls made of brick, stucco, concrete block and cement board in a field installation.
Preliminary findings released this year are part of a three-year research program.
Initial results show that EIFS walls are better at protecting buildings from moisture while offering superior thermal
control. Achilles Karagiosis, Ph.D., of the Building Envelope Group of the Oak Ridge National Laboratory
issued a summary of the research findings on September 19, 2006. The ORNL’s researcher asserted that the research is
“useful … in demonstrating the superior moisture and temperature control performance of EIFS as compared with
other types of exterior claddings.”
The researchers used instrumentation that precisely and continuously monitored and recorded the side-by-side performance
of typical wall assemblies in defending against common environmental challenges such as moisture and temperature swings over
the 15 month period. Each wall claddings alternative was incorporated into a specially constructed building located
in Charleston, South Carolina, for comparison and evaluation.
Moisture intrusion can cause rust, rot and other structural damage. The study found that house wraps permitted more
moisture accumulation than water-resistive barrier coatings, which are sprayed on. In addition, “the use of polyethylene
vapor retarders is not a good strategy,” reads the ORNL summary.
The study also provides insights as to the best ways to insulate buildings. “Insulation is more beneficial when
placed toward the exterior,” says the summary.
Highlights of the memo, titled “The Hygrothermal Performance of Exterior Wall Systems: Key Points of the Oak
Ridge National Laboratory NET Facilities Research Project” include:
- BACKGROUND: The 3-year testing program was initiated and funded through the U.S. Department of Energy
(DOE) and in part by a nonprofit trade group, the EIFS Industry Members Association, or EIMA. The study was conducted independently
by the Oak Ridge National Laboratory (ORNL), which is funded by DOE.
- RESEARCH METHOD: Goals of the ORNL study were to confirm the performance of EIFS for insulating ability
and moisture resistance. Field research was conducted for 15 months on a specially made test building constructed with various
cladding materials and fitted with sensors to record moisture content, humidity, temperature and other variables. EIFS walls
are compared to brick, stucco, cement board and concrete block. The field data are being used to create a computer simulation
intended to predict wall performance of the subject variables, called a hygrothermal model.
- SCIENTIFIC RESULTS: The study demonstrates that “the best performing wall system was the EIFS wall
consisting of 4 inches of expanded polystyrene insulation board without any interior stud insulation (no fiberglass),”
reads the study summary issued by ORNL. “This wall outperformed all other walls in terms of moisture while maintaining
superior thermal performance.”
For more information on the study, contact Stephan E Klamke, Executive Director,[sklamke@eima.com] at the EIFS Industry
Members Association, or Achilles Karagiozis, Ph.D. at the Oak Ridge National Laboratory [karagiozisan@ornl.gov].
ABOUT THE OAK RIDGE NATIONAL LABORATORY: A multiple-program science and technology organization funded
through the U.S. Department of Energy (DOE), Oak Ridge National Laboratory (ORNL) conducts basic and applied R&D in many
areas of science and technology. ORNL is managed by UT-Battelle LLC for the DOE, and is based near Knoxville, Tennessee. Scientists
and engineers employed at ORNL build scientific knowledge and technological solutions to increase the availability of clean,
abundant energy; restore and protect the natural environment; and contribute to national security. (For more information,
see www.ornl.gov.)
ABOUT EIMA.: Founded in 1981, the EIFS Industry Members Association (EIMA) is a national non-profit
technical trade association of leading manufacturers, suppliers, distributors and contractors involved in the exterior insulation
and finish systems (EIFS) industry. (For more information, see www.eima.com.)
ABOUT E.I.F.S.: The term Exterior Insulation and Finish
Systems, or EIFS, refers to a system of wall construction that comprises foam insulation board, a fiberglass
mesh and an engineered series of performance and decorative coatings, including barriers to water and air. EIFS assemblies
are usually attached to and supported by building framing and sheathing. The finished surface, which can be colored and textured,
often has a stucco-like appearance.
