EIFS Stucco Explained
EIFS stucco is a complicated stucco system and may be confusing for some people. In order to understand this system you have to get a better idea of what it is used for, what goes into it, and what are its advantages and disadvantages compared to other stucco systems.
What is EIFS Stucco?
EIFS (Exterior Insulation Finishing System), also known as EWI (Exterior Wall Insulation System) or ETICS (External Thermal Insulation Composite Systems) is a type of stucco wall cladding that looks similar to a typical stucco installation on the outside. All EIFS cladding is designed to keep the moisture out on the surface level. Therefore, this is the perfect energy efficient thermal wrapping or façade insulation that can be applied to the exterior surface of a building creating a long-life, decorative and protective wall coating that can be installed on almost any type of construction. It usually has an acrylic type of finish but what differs it from a hard coat stucco system are the inner layers.
Parts of EIFS Stucco
EIFS uses multiple layers of various products with special properties like increased air barriers or improved water protection to create a complete wall system. Exterior Insulation Finishing System typically consists of six layers: A water/air barrier, an adhesive basecoat, foam, a base coat that is embedded into a fiberglass mesh, a primer coat, and a finish coat
Water Resistive Barrier (WRB) is a sometimes optional part of EIFS cladding that gives the wall more water resistance. Fluid applied WRBs are applied like paint. They are usually rolled, brushed, or sprayed on. It is important that this coat does not have any pin holes because it is waterproofing and any holes would allow the water to come in and be trapped inside the walls. Another type of WRBs is a form of asphalt infused paper that can be found on a hard coat system as well.
The Adhesive basecoat acts like a strong glue and is used to attach the foam to the supporting structure. It is usually applied vertically, using a notched trowel. Adhesive is not mandatory for all EIFS claddings. Sometimes the foam is mechanically fastened to the wall and an adhesive is not needed.
The Foam insulation board is usually the main insulator for the wall. It is typically made from an eps type of foam and has grooves on the back side that run up and down allowing the water to drain if it has gotten somehow inside the system. The foam board can be attached using an adhesive or it can be attached mechanically, using staples, screws or nails.
The Base coat is applied on the top of the insulation and then always has to be reinforced with glass fiber mesh. It is made of acrylic or polymer-based cement material.
A Primer coat is a coat of paint that is applied prior to the finish coat and in some cases is optional. Manufacturers recommend using a primer coat because it acts as a seal for the base coat and helps provide an even suction on the wall, creating a much better and consistent end result.
The last coat that goes in the EIFS cladding system is the finish coat. It is a textured coat that provides protection and adds a nice look to the building. Similar to a hard coat stucco system, the EIFS finish coat is typically made of an acrylic material.
Advantages and Disadvantages of EIFS Stucco
The biggest benefit of the EIFS cladding system is the increased insulation it provides. It is far more flexible than hard stucco systems due to its shifting foundation and thermal expansion. Therefore, there is less cracking and crumbling. Unlike EIFS, traditional stucco systems are prone to water damage and cracking, peeling, and chipping during time. Moreover, the fiberglass mesh increases its durability, even against weather impact. EIFS is also energy sufficient. It can reduce air infiltration by up to 55%, in comparison to wood and brick constructions.
On the other hand, EIFS stucco installation is much more complicated than traditional stucco (more on this here). There is a high risk of errors during installation which can result in a lack of water resistance and long-term damages. Therefore, it is recommended to be installed by a trustworthy and experienced professional contractor. Nonetheless, EIFS prices are significantly higher in comparison to traditional stucco.
