Exterior Insulation and Finish Systems (EIFS) is commonly referred to as synthetic stucco or Dryvit. EIFS was developed in Germany during the 1950's as one of many revolutionary building materials or systems to assist in the re-building of Europe after World War II. The product has evolved over the ensuing years and there are currently over a dozen manufacturers, the most prominent being Dryvit, Senergy, Sto and Parex.

As you travel from coast to coast you can see thousands of hotels, motels, office buildings, strip malls and homes clad with EIFS in more architectural variations than you could imagine. In addition to the almost unlimited design capabilities, EIFS is also very “energy efficient”, as it provides a virtual blanket for the exterior of a structure through the use of expanded polystyrene or EPS foam insulation.

There are two types of EIF systems, “Barrier EIFS” and “Water-Managed” or “Drainage” EIFS (see illustrations). Although Water-Managed EIF systems have been available since around 1996, most EIFS applications prior to 2000 utilized the barrier system.

In a typical EIFS application the EPS or PI foam board is mechanically and/or adhesively fastened to an approved substrate. A fiberglass reinforced mesh is then applied to the foam board and fully imbedded in a basecoat. After the basecoat is cured (usually 24 hours) the finish coat, which gives the wall its stucco appearance is then applied. 

Some Concerns
In the mid-‘90s concerns arose over the performance of EIFS. As many EIFS homes were inspected, moisture intrusion and damage to sub-sheathing and framing was frequently discovered. Many theories have espoused regarding this issue, these theories range from misapplication of EIFS materials, improper interface of EIFS with other components (such as windows, doors, and flashing), and defective construction materials-- to an all out condemnation of EIFS.

Some would argue that the barrier EIF system is inherently flawed as it makes no allowance for even incidental moisture to escape from behind the EIFS cladding. Therefore, in order to maintain the integrity of the barrier system, the design professional and/or general contractor is relying primarily on sealants to keep moisture from intruding - and in fact all sealants will eventually fail. It’s important to note that moisture intrusion is a normal occurrence in all types of construction, both residential and commercial, brick, cedar, stone, aluminum, vinyl siding and even water-managed EIFS. Because EIFS is easier to inspect it has naturally come under more scrutiny than most other claddings. But this could also be viewed as an advantage, in that other types of cladding are difficult to inspect and therefore moisture intrusion and damage could go on for many years before it is discovered.

We have found that most often when moisture intrusion and damage occurs, regardless of the exterior cladding, it occurs at areas of transition between the exterior cladding and other materials such as window frames, door sills, utility penetrations, balcony and deck attachments and roof flashing. Extensive structural damage can occur when water intrusion is large in volume and frequent. If left undetected, prolonged moisture build up can cause damage to sheathing, structural framing and other materials, some of which are also susceptible to microbial growth (mold) and in the case of steel framing, corrosion.