What is EIFS?
March 29, 2009
EIFS is an abbreviation for “exterior insulation and finish system,” also called fake stucco or synthetic stucco. It is a type of low-cost, waterproof exterior finish with high insulation value.
EIFS Components
EIFS components are applied in several layers.
- The first layer is a foam board applied to the building’s exterior to provide insulation.
- Next, a stucco-like base coat is troweled onto the foam, and a fiberglass mesh fabric is embedded in the base coat to create mechanical strength.
- A thin stucco-like finish coat in a choice of colors is then applied for appearance.
EIFS History
EIFS was introduced in Germany following World War II where it was widely used as an inexpensive system for repairing masonry buildings.
In the late 1960’s EIFS started being used in commercial buildings in the Untied States. In addition to its low-cost, the attraction to EIFS was the ability to apply intricate foam shapes to create ornate exterior trims that resembled carved stone.
By the 1980’s, EIFS began to be used in residential construction. Its use for homes was also driven by its versatility and favorable cost.
EIFS Problems
Not long after EIFS started being used in residential buildings, problems began to surface. Homeowners began discovering major wood-rot issues were occurring behind the foam insulation. EIFS claims became so common that they led to several class action lawsuits being filed in the 1990s.
The cause of the wood-rot problem is two-fold.
First, because EIFS is a waterproof barrier, it is excellent at keeping water out of a building. But if any water does happen to get through, EIFS then becomes excellent at keeping the water in. When the trapped moisture is absorbed by the wood framing inside the walls and reaches 20% saturation, wood destroying algae begin to thrive.
Second, windows, doors, and other wall openings or penetrations are the weak points in the waterproof barrier. If not properly sealed, water is able to get behind the foam and become trapped. A single mistake in applying flashing or caulk, or failure to properly maintain the sealant over time can result in water intrusion. Also, making new penetrations (such as in hanging a hose reel) without properly sealing them can also create the problem.
The Solution
Because the fundamental problem with barrier EIFS is that water cannot escape from behind the foam, the industry developed an alternative system that provides the same type of drainage that real stucco uses. The alternative system is referred to as drainage EIFS.
When applying drainage EIFS, the building is first wrapped with a waterproof building paper and the foam is applied so there is a minute space between the foam and building paper for moisture to drain. This system is a little more expensive than barrier EIFS, but is much easier to install properly, thus reducing the potential for water intrusion problems.
EIFS Today
Barrier EIFS is still popular in commercial construction. The incidence of problems in commercial buildings is lower because the quality of the work is generally much higher. Barrier EIFS still works and can be problem free when properly applied and maintained.
Barrier EIFS also still exists in residential construction, although its use has diminished significantly because of the bad press it’s gotten. Drainage EIFS is often preferred where a low cost, ornate exterior trim is desired. Some builders employ hybrid systems using traditional stucco for most of the building and EIFS for trim.
Where barrier EIFS is still used, it’s most often used in conjunction with a qualified inspection service to insure that it has been installed properly.
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