Masonry Magazine October 1997 Page. 32
A restaurant in Texas that had to be rebuilt because of extensive water leaks in the EIFS.
ing jobs where the structural support systems cannot carry the additional weight of heavier exterior finish materials.
A recent search on the Internet by the author using the key words "exterior insulation and finish systems" found over 23 million listings on one search engine alone. Refining the search to "EIFS" found 311 listings. Examination of these found that over 75% of the articles or postings on the Internet discussed problems with EIFS. The remainder of the postings were from manufacturers, installers, and trade associations and generally extolled the positive features of the material or included technical information about it.
According to most industry records, EIFS were brought to North America in 1969. They found widespread use in commercial construction in the United States during the 1970s, and by the 1980s, home builders began using EIFS on residential projects with greater frequency.
Water Management in Synthetic Stucco Systems
Exterior insulation and finish systems commonly use the surface barrier approach to maintaining water-tightness in the building envelope. The surface barrier design requires that 100% of the water that comes into contact with walls from rainfall or from roof runoff be diverted at the surface. In principle, this is accomplished by tightly sealing all of the joints or openings in the material with caulk sealants and the use of flashings and so on.
Water damage in the gypsum board sheathing at a window.
In the typical United States application, the insulation board is typically attached directly to a substrate made of plywood, oriented strand board, exterior grade gypsum board, or other similar sheathing. There is no cavity or drainage plane behind the exterior insulation and finish system like one will find in a brick cavity wall, or on a conventional stucco finish with a moisture retarder behind it. With the assistance of forces such as capillary action, gravity, and/or wind pressure, water that gets past the surface coatings works its way into the substrates and sometimes into the wall framing system and insulation behind the EIFS. Herein lies the most serious criticism of the common U.S. application of EIFS. The non-drainable exterior insulation and finish systems, the most popular and the most economically priced, have no efficient way of returning this water directly to the exterior like masonry cavity walls do.
When water enters through cracks in the surface barrier system, and there is a statistical probability that every building's cladding system will leak water at some point over its life-time, just as it will with EIFS, the wall framing and sheathing may take a long time to dry out. The insulation board traps the water so it cannot evaporate on the outside of the wall, and the vapor retarder on the inside of the wall slows its evaporation towards the inside of the building. In areas where rainfall occurs frequently, dampened wall sheathings and wood framing members cannot dry out. Excessive moisture in building materials supports the growth of damaging organisms, or causes chemical and physical deterioration of substrates such as exterior grade gypsum boards and their paper faces. Corrosion of metal fasteners and metal studs in walls is also supported by this moisture.
Unfortunately, this damage is not visible to the typical building owner during a casual inspection. The damage can occur rather rapidly too, as buildings less than one year old have
Synthetic stuccos were developed in Sweden in the 1930s and were used widely in Europe by the 1950s. In Europe they have enjoyed a good, long history as a building cladding material for reasons which are given later. However, the story is not the same in the United States.