Let's take a look at some of the parts of an EIFS cladding to get a better breakdown of what's involved and this will really help you understand what they are, what they consist of and how they differ from a hard coat stucco system.
The wall will usually have mechanical fasteners (nails, screws, etc.) that attach the foam insulation to the substrate and is why this type of WRB is used (self healing properties).
The foam board is usually made from an EPS type of foam but can vary based on manufacturer and can have grooves on the back side that run vertically (up and down) to allow water to drain if it is ever present in the system.
Not all foam will have grooves on the backside though, just something worth noting.
The foam board can be attached mechanically, using staples, nails or screws or it can be attached using an adhesive, which is specifically designed to attach foam to other surfaces and acts as a very strong glue.
The adhesive is usually applied vertically, using a notched trowel.
The mesh is usually a fiberglass type of mesh that comes on a roll, like what you would typically use for drywall, but is much larger and can be found 3' wide by 100' long or longer. There are also different weights of mesh that provide different impact resistance ratings, the thicker the mesh, the more impact resistant it will be.
The primer coat is optional (in most cases) but I always recommend a primer coat because it will seal the base coat which nearly eliminates any possibilities of the base coat flaking off and getting into the finish coat.
It actually helps to provide an even suction on the wall too, making for a much better and consistent end result.
Having a primer coat will also allow the finish material to go much further because it eliminates a lot of the suction, which tends to eat up more finish material during the application process.
Manufacturers will sometimes state that their warranty is void if a primer is not applied prior to the finish being applied, so you will want to check to see if that is true or not in your situation.
EIFS cladding is typically designed to keep out moisture from the outermost layer, which happens to be the finish coat, so the material will have to be water-resistant to be effective.
The finish can be made up of an acrylic material, but it is important to note that an EIFS wall cladding may require a different type of finish material than a hard coat stucco system will require. Most manufacturers have specific finishes for their EIFS cladding system and it is important to follow their recommendations, if using their specific system.
