Exterior Insulation and Finishing Systems (EIFS) Information

An EIFS on half of a residence.Exterior insulation and finishing systems (EIFSs) are multilayer, non-load bearing overlays that protect and insulate the exterior walls of a structure. EIFSs effectively reduce heat transfer between a building and the environment. They are versatile in their aesthetic and are ideal protection for residences and businesses.    

EIFSs are composed of a substrate, adhesive, insulation board, reinforcement mesh, base coat, primer, and finishing coat, at minimum. Polymer-based EIFSs are most common.


There are two general types of EIFSs: barrier wall systems and wall drainage systems. Barrier wall systems use the base coat of the exterior for weatherproofing. All associated components must conform to this system. Drainage types are installed over a weather barrier or substrate and are a supplementary runoff conduit. Flashing, sealants, or wiring fasteners might be installed as well. 

Barrier wall systems have inherently poor drainage. Compared to the wall drainage systems, barrier wall systems have no drainage system, resulting in the potential to trap moisture and water behind the system, which can cause mold growth and structural degradation. Wall drainage systems allow the flow of water and moisture to escape the system, thereby preventing the containment of water and moisture. Wall drainage systems are currently the most used EIFS due to the robust properties of the system, such as the ability to patch damaged sections of the system as well as the ability to prevent the buildup of water in the system.

Image credit:

Handwerker/CC BY-SA 3.0