Bob describes the basics of what happens to EIFS when the material is struck and damaged.
In the early days of the EIFS industry in North America, the damage resistance of EIFS from impact was a big issue. Architects and building owners want to know how EIFS fared when walloped, and competitors, looking to regain market share lost to the growing use of EIFS, fueled the fire by trying to make an issue out of impact resistance. EIFS manufacturers looked for solutions to the impact question and found them. This month's column describes the basics of what happens to EIFS when you bash it, and will no doubt give you some ammo for explaining the impact issue to those who still have questions.
Contrary to popular belief, the mesh in an EIFS basecoat is not used there primarily to provide impact resistance. In fact, a functional but not very impact-durable EIFS-type cladding can be built with mesh only at the insulation joints. This requires some snazzy basecoat formulating, such as integral fiber reinforcing, but it is possible. The primary function of the mesh is to keep the edge of the insulation pieces together as they expand and contract. Without the mesh at the joints the coatings would crack at that point. The problem with not using mesh in the field of the insulation boards is that even a mild hit there would crack the EIFS coatings. It's simply not practical to put mesh only at the insulation joints, so don't even think about being cheap and trying it.