An Exterior Insulation Finishing System (EIFS), also known as EWI (Exterior Wall Insulation Systems) or External Thermal Insulation Composite Systems (ETICS) is a type of cladding system that provides exterior walls with an insulated finished surface and waterproofing in an integrated composite material system. Put another way, an Exterior Insulation Finishing System / External Thermal Insulation Composite Systems can be defined as an ideal energy efficient thermal wrapping or facade insulation applied to the exterior surfaces of a building which is then finished with a long-life, decorative and protective wall coating that can be installed on any type of construction.

In the construction industry, there are a number of versions of EIFS / ETICS. The most basic and common EIFS / ETICS is called a barrier EIFS, also known as traditional or conventional EIFS / ETICS, which is applied to a solid wall (brickwork, blockwork, pre-cast panels and the like). Another type is called EIFS / ETICS with drainage, which is a barrier EIFS / ETICS to which a water drainage capability has been added. This is done mainly for wood structures.