What is EIFS - Synthetic Stucco?

Synthetic Stucco Explained

Color samples of paint, stone, granite, stucco and tile sitting on top of blueprints
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EIFS is an acronym for "Exterior Insulation and Finish Systems." The product is also called synthetic stucco, and it refers to a multi-layered exterior finish that's been used in European construction since shortly after World War II.

Contractors found stucco 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 when, in fact, the exterior siding is actually EIFS.

EIFS in North America

The EIFS Industry Members Association states that EIFS first came to the U.S. in 1969.

Many North American builders began using EIFS in the 1980s, first in commercial buildings then applying it as an exterior finish to residences, mostly wood frame houses. They used the same techniques that had been successful in Europe.

EIFS Has Six Layers

Unlike earlier applications, there are six layers to modern EIFS:

  1. An optional water-resistive barrier is generally fluid that's applied to cover the substrate.
  2. Adhesive attaches insulation board to the supporting structure. Mechanical fasteners can be used in some cases.
  3. A foam insulation board is secured to the exterior wall surface substrate, most often with adhesive.
  4. A base coat, either an acrylic or polymer-based cement material, is applied to the top of the insulation then reinforced with glass fiber reinforcement mesh.
  5. The reinforcement mesh is embedded in the base coat material.
  6. The finish is a textured coat that's decorative and protective.

Moisture Issues

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

Constant exposure to moisture can lead to dry rot in wood when moisture has no place to go. This problem can be discovered through a routine pest inspection.

A Word From the EIFS Industry Member Association

What worked well as an exterior shell for concrete and stone became a problem when it was used on wood. Moisture-related problems have led to individual and class action lawsuits by consumers.

EIFS isn't the only product responsible for water seeping behind the finish, however. Water can intrude into traditional stucco as well.

The EIFS Industry Member Association reports the following:

"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." 

Newer EIFS systems include a drainage arrangement to help keep moisture from becoming trapped behind the covering.

Ask a trusted homebuilder for details about contemporary EIFS. Both traditional and EIFS stucco rely on secondary drainage systems to keep your basic structure dry.

How to Recognize Synthetic Stucco

Synthetic stucco is soft and sounds hollow when it's tapped, while traditional stucco is hard and brittle. It sounds solid when it's tapped.

Press against the structure with your thumb. It's EIFS if you can feel the finish deflect.

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, typically around window openings.

You most likely have EIFS stucco on your home if you can spot foam board around light fixtures or door frames.

Maintaining EIFS

Any opening, such as door and window frames and the areas around flashings, should be sealed to prevent water from seeping behind the EIFS.

Gutters should be kept clean and positioned to drain away from the house, and 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 can be a warning sign of a problem, as can swollen wood around door and window frames. Blistered, bubbling, or peeling paint can indicate a problem, as well as cracked EIFS or sealant.

​Cleaning EIFS

Any home exposed to the elements over a long period of time will eventually require cleaning, and EIFS is very easy to clean.

You can make your own cleaning solution at home by combining two cups trisodium phosphate, one cup bleach, and one gallon warm water. Apply the solution by brush or spray, then allow it to soak for 15 minutes. Brush lightly with a soft brush, then rinse.

Stucco Exteriors vs. Vinyl Siding

Stucco exteriors can last up to 50 years or more, but they seem to do better in hot, dry climates rather than cold, wet, rainy areas. You'll probably find more stucco homes in California, Texas, Florida, Arizona, and New Mexico.

Vinyl siding fares better in colder climates that are prone to extreme swings in the weather, such as Minnesota or New York. Vinyl moves with the house—when it's cold, it contracts, and when it's hot, it expands.

Of course, a house with vinyl siding isn't nearly as pretty as a stucco house, whether the finish is traditional stucco or EIFS.