Exterior Insulation and Finish Systems (EIFS) are multi-layered exterior wall systems that are used on both commercial buildings and homes. They provide superior energy efficiency and offer much greater design flexibility than other cladding products.
Developed in Europe in the 1950s, EIFS were introduced in the U.S. almost 40 years ago. They were first used on commercial buildings, and later, on homes. Today, EIFS account for nearly 30% of the U.S. commercial exterior wall market. EIFS typically consist of the following components:
- insulation board, made of polystyrene or polyisocyanurate foam, which is secured to the exterior wall surface with a specially formulated adhesive and/or mechanical attachment
- a durable, water-resistant base coat, which is applied on top of the insulation and reinforced with fiber glass mesh for added strength
- an attractive and durable finish coat — typically using acrylic co-polymer technology — which is both colorfast and crack-resistant.
The growing popularity of EIFS is due to the fact that few, if any, competitive materials offer such a wide range of desirable product benefits. Chief among these are superior energy efficiency and virtually unlimited design flexibility.
If you’ve ever felt the comfort of being wrapped in a warm blanket on a cold winter night, you have some idea of what EIFS can do for a home or building.
EIFS literally wrap the exterior in an energy-efficient thermal blanket. By insulating outside the structure, EIFS reduce air infiltration, stabilize the interior environment and reduce energy consumption.
By contrast, traditional “between-the-studs” insulation, no matter how thick, leaves “thermal breaks” — gaps where heat and cold pass more freely between the outdoors and the space within — at studs, wall outlets, wall joints, and elsewhere.
In fact, EIFS can reduce air infiltration by as much as 55% compared to standard brick or wood construction. And since walls are one of the greatest areas of heat and air conditioning loss, improvement in the wall insulation can be very meaningful in terms of energy conservation.
What’s more, EIFS add to the “R-value” of a home or building. (R-value is a measurement of the resistance to heat flow; the higher the R-value, the better the material’s insulating value.) Most EIFS use insulation board with an R-value of R-4 to R-5.6 per inch as the innermost layer in the wall system. When combined with standard wall cavity insulation, this extra layer can boost wall insulation from R-11 to R-16 or more.
Another point to keep in mind on new construction: Due to the energy efficiency of EIFS, it may be possible to specify lower-capacity heating and air conditioning equipment without sacrificing anything in terms of interior comfort.
The rich appearance of EIFS bears a resemblance to stucco or stone, but the systems are far more versatile than these and other materials. Not only do EIFS come in virtually limitless colors and a wide variety of textures, but they also can be fashioned into virtually any shape or design.
With EIFS, skilled applicators can create all sorts of exterior architectural detailing that would often be cost-prohibitive using conventional construction — cornices, arches, columns, keystones, cornerstones, special moldings and decorative accents are but a few examples.
Most of this detailing is computer-generated. The designs are precision-cut out of insulation board, attached to the substrate or wall, then covered with the EIFS base coat, mesh and finish coat.
Using this ingenious process, EIFS applicators can give a striking, distinctive appearance to any building or residence.
Unlike wood, stucco and other siding materials, EIFS rarely need painting. Most EIFS systems are specially formulated with 100% acrylic binder, which gives EIFS superior resistance to fading, chalking and yellowing. As a result, the systems tend to maintain their original appearance over time. And since the color is integral to the finish coat, even if the surface is scratched, the same color appears beneath the abrasion.
EIFS also have excellent resistance to dirt, mildew and mold, which helps keep the building exterior looking clean and freshly painted. Should the surface ever become soiled, it can usually be cleaned by hosing it down.
The systems are designed to be very flexible, which makes them highly crack resistant. When walls expand or contract due to rising or falling temperatures, EIFS are resilient enough to “absorb” building movement and thus avoid the unsightly cracking problems that are so common with stucco, concrete and brick exteriors.
EIFS are among the most water resistant exterior surfaces you can put on a house. But as with all claddings, EIFS must be correctly installed and properly detailed if they are to perform properly. Otherwise, moisture can get behind the systems and cause damage, just as it can with wood siding, brick or any other exterior.
Water intrusion is seldom a problem on commercial structures with EIFS. Water intrusion damage to homes is uncommon, but when it does occur, the moisture typically affects only small areas which can be easily and inexpensively repaired.
In cases where homes have been damaged, the problems have been traced to the use of poor quality (even leaky and/or non code-compliant) windows and/or improper flashing and sealing. As a result, when building with EIFS, it is wise to use quality windows (such as those with AAMA certification) which are code-compliant, and to make sure there is proper flashing and sealing around windows, doors, roofs, deck-to-house attachments, and all other exterior wall penetrations.
Used with permission from:
EIFS Industry Members Association (EIMA)
513 West Broad Street, Suite 210
Falls Church, VA 22046-3257.