Exterior Insulation and Finish Systems (EIFS) are a relatively new cladding system that combines a finish with a layer of exterior insulation. The finish is comprised of polymeric (organic) bonded aggregate and cement reinforced with a glass mesh. Stucco is a cladding made of inorganic-cement (Portland cement and/or lime) bonded sand or earth used for thousands of years. Despite the obvious visual similarities; these two claddings perform very differently.
EIFS system can come with built-in drainage which is significantly different from face-sealed systems in which they have provisions for dispelling water. Unlike its counterpart, face-sealed are recognized for the full barrier systems assembly which can successfully be used as an exterior cladding system in all climates. It should be noted that EIFS with built-in drainage systems is not subject to the same limitations of use as face-sealed. In fact, drainage EIFS are amongst the most advanced moisture control assemblies available on the market to date.
Traditional stucco constructed with Portland cement base is a definitive and successful example of a storage approach to rain control. A vapor permeable paint is often used over the stucco rendering to reduce rainwater absorption while still allowing drying to the exterior. The rainwater that enters through the stucco face is harmlessly stored in the masonry wall until it can dry to either the interior or to the exterior.