Once in awhile, an unusual problem surfaces with EIFS that defies an easy explanation. One of the more interesting ones in the recent history of EIFS had to do with reinforcing mesh that had problems with the plastic coating on it. This problem surfaced first in the '80s and recently has reared its head again. It's worth going over this saga, so if it happens on some job you're involved with, it's good to have some idea of what is going on.
As background, we all know that the reinforcing mesh used in EIFS is made of glass. The type of glass is the ordinary type used for drinking glasses. We also all know that many EIFS basecoats use Portland cement. Portland cement is alkali (caustic). Caustic materials can etch glass. The etching causes the surface of the glass to have microscopic fissures. These fissures act as a point at which a crack can begin. Being a brittle material, cracks in glass propagate easily. In the case of EIFS, this means that the mesh loses its strength and the EIFS lamina may crack. Cracks can let water in, along with lawyers.