Anyone with even a little bit of experience with EIFS can tell war stories about getting dragged into situations in which the EIFS on a building is supposedly leaking. It’s almost a waste of time to state once again that the EIFS itself virtually never leaks, but still the wall is considered “an EIFS wall,” and hence the EIFS is supposedly to blame. So if the EIFS itself is not leaking then what is?
Leaks almost always occur at the edge of the EIFS, such as at a flashing, an adjacent wall element (such as a window or deck beam penetration) or a sealant joint. Sealants are notorious causes of leaks and there are many reasons for this. Besides the obvious issues, such as the sealant reaching the end of its life or the joint not being properly designed or installed, there are lots of other causes.