That is also an area where fasteners may be applied. A strip of mesh is then based over the joint. The application of the final finish coat completes the process and the joint becomes concealed. Some jobs require joints to be shown, perhaps to create an appearance similar to cast stone. In those cases the shapes could be ordered with complete base coat coverage along the entire length of the shape.
Mechanical attachment is necessary.
Mesh in those back-wrapped areas can then be pulled away from the back of the shape during installation and used to base into the wall for a more secure attachment and to keep water from getting behind the shape. The area of the shape that will be base-coated and meshed needs to be specified by the Plastering Contractor at the time the shape is ordered. Please bring your questions and suggestions to your EIFS distributor or call us. The normal method of fasteners or nails clearly won't attach to concrete. But something is needed to hold the shape firmly in place while the adhesive is setting.