What is EIFS - Synthetic Stucco?

eifs stucco
You can paint an EIFS stucco house. © Big Stock Photo

What is EIFS?

EIFS is an acronym for Exterior Insulation and Finish Systems. The product is also called synthetic stucco  and refers to a multi-layered exterior finish that's been used in European construction since shortly after World War II, when contractors found it to be a good repair choice for buildings damaged during the war. The majority of repairs to European buildings were to structures constructed of stone, concrete, brick, or other similar, durable materials.

Some homeowners might think their home is made from traditional stucco and are often astonished to discover the exterior siding is EIFS.

EIFS in North America

Although the EIFS Industry Members Association says EIFS came to the Untied States in 1969, many North American builders began using EIFS in the 1980's, first in commercial buildings, then applying it as an exterior finish to residences -- mostly wood frame houses -- using the same techniques that had been successful in Europe.

Unlike earlier applications, there are now 6 layers to EIFS

  1. An Optional Water-Resistive Barrier that is generally fluid applied and covers the substrate.
  2. Adhesive to attach insulation board to the supporting structure (in some cases mechanical fasteners may be used).
  3. Foam insulation board that's secured to the exterior wall surface substrate, most often with adhesive.
  4. Base Coat, an acrylic or polymer-based cement material that's applied to the top of the insulation, then reinforced with glass fiber reinforcement mesh.
  1. Reinforcement Mesh, that is embedded in the base coat material.
  2. Finish, a textured finish coat that is decorative and protective.

EIFS layers bond to form a covering that doesn't breathe. That's fine when no moisture is present behind the covering, but if moisture seeps in it can become trapped behind the layers.

With no place to go, constant exposure to moisture can lead to dry rot in wood, which can be discovered through a routine pest inspection.

What had worked well as an exterior shell for concrete and stone became a problem when used on wood. Moisture-related problems lead to individual and class action lawsuits by consumers. However, bear in mind that EIFS alone is not responsible for water seeping behind the finish as water can intrude into traditional stucco as well.

The EIFS Industry Member Association reports the following and has asked me to include this in our article:

"EIFS layers bond to form a wall covering that is weather resistant and vapor permeable.  As with any cladding, prevention of water infiltration into and behind it is important for long term durability. Over the last decade or so, several advancements to EIFS have been made. One is a drainage cavity that is behind the foam insulation.  This cavity is achieved either with vertical ribbons of adhesive, an insulation board configured with vertical grooves on the back, or in some cases, a drainage mat. Another is a supplemental component called a WRB, or Water-Resistive Barrier. This component provides additional moisture protection to the structure and is applied directly onto the supporting substrate.

"These advances address some of the issues that arose in the late 1990s when some homes that were covered with EIFS cladding suffered damage from water intrusion. ​An investigation into the damage showed that water was not infiltrating through the EIFS, but was infiltrating through leaky windows or poorly constructed details. At the time EIFS was the target of individual and class action lawsuits, although other claddings, including brick, stone, wood and vinyl siding, and conventional stucco, showed similar damage when installed with similar leaky windows and poor construction detailing." 

Synthetic Stucco vs. Traditional Stucco

  • Synthetic stucco is soft and sounds hollow when tapped.
  • Traditional stucco is hard and brittle and sounds solid when tapped.
  • Press against the structure with your thumb, if you can feel the finish deflect, it is EIFS.
  • Look for cracks. Traditional stucco is more prone to cracking and the cracks are usually much longer than the smaller cracks typically found in EIFS such as those around window openings.

Maintaining EIFS

  • Any opening, such as door and window frames and the areas around flashings, must be sealed to prevent water from seeping behind the EIFS. If you can spot foam board around light fixtures or door frames, for example, you most likely have EIFS stucco on your home.
  • Gutters should be kept clean and positioned to drain away from the house.
  • Foam should not extend below grade.
  • Items that penetrate the stucco must be sealed.

In other words, no moisture should be able to seep behind the EIFS.

Signs of EIFS Problems

  • Mold or mildew on the interior or exterior of the home.
  • Swollen wood around door and window frames.
  • Blistered, bubbling or peeling paint.
  • Cracked EIFS or cracked sealant.

EIFS Today

Newer EIFS systems include a drainage arrangement to help keep moisture from being trapped behind the covering. Ask a trusted home builder for details about contemporary EIFS. Both traditional and EIFS stucco rely on secondary drainage systems to keep your basic structure dry.

You will find stucco and EIFS homes all over the United States. Stucco exteriors can last up to 50 years or more, but they seem to do better in hot, dry climates than cold or wet, rainy areas. You will probably find more stucco homes in California, Texas, Florida, Arizona and New Mexico. In colder climates such as Minnesota or New York, for example, vinyl siding fares better due to extreme swings in the weather because it moves with the house. When it's cold, the vinyl contracts and when it's hot, it expands.

Of course, then you have to look at a house with vinyl siding. And it's not nearly as pretty as a stucco house, whether the finish is traditional stucco or EIFS.

Edited by Elizabeth Weintraub, Home Buying / Selling Expert, with the assistance of Scott Robinson, Director of Public Affairs, EIFS Industry Members Association.

At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.