The increased utilization of Exterior Insulation and Finish Systems (EIFS) as the primary component of exterior building envelopes for projects ranging in size from small commercial buildings to major high-rise structures has continued unabated for several years now. As new market regions within the United States and the installation work force in these areas are introduced to the use of this building material, there is a natural “learning curve” pertaining to its proper use, limitations, and potential disadvantages. Architects, designers, project supervisors, and local craftsmen are required to acquire a fundamental knowledge of the correct use of EIFS in order to avoid potential problems. This paper presents some of the practical problems being experienced today in regard to this new technology. Although it does not present a specific case study, this paper draws from the experiences of investigation and analysis on dozens of different projects nation wide, some of which were experiencing severe problems related to moisture infiltration. It discusses common mistakes and typical abuses observed in a large percentage of the projects reviewed. In addition, an attempt is made to address correct usage of this increasingly important material by applying well established principles of basic building technology. This paper is intended to assist in achieving the best performance and service life available from this particular building material by disseminating knowledge gleaned from experience with past problems in existing buildings.