A Case Study of Construction Challenges and Solutions: Installation of Exterior Insulation and Finish System (EIFS) to an Existing Residential Structure

Abstract

Demand for exterior insulation and finish systems (EIFS) as an option for retrofitting existing buildings is increasing. EIFS provide a practical, energy-efficient solution for achieving goals that are being driven by changes to building codes, increased energy costs, and environmental sustainability. This paper presents a case study of the construction challenges and solutions employed in the installation of EIFS as a retrofit cladding onto an existing single-story, wood-framed residence in Brunswick, ME. The residence was originally constructed in the 1960s and insulated with fiberglass batt in the stud cavity, wood plank sheathing, and lapped wood siding. A previous retrofit project completed in the 1980s encased the original siding with 1 in. of foil-faced polyisocyanurate insulation board and vinyl siding. The 2013 EIFS retrofit project described in this paper included removing the existing siding and exterior foil-faced insulation board while leaving the existing doors and windows in place. Construction of the new cladding included application of a fluid-applied air and moisture barrier to the original siding and installation of an exterior insulation system using 6-in.-thick (150 mm) extruded polystyrene insulation. Code compliance implications of adding combustible insulation to the exterior of the house were considered. In this case, the structure is a wood-frame combustible house, and the retrofit did not result in a change in code compliance with regard to fire performance. Every retrofit project presents unique challenges, but the resolutions of these challenges often share common concepts and design/construction approaches. This paper provides information regarding specific detail configurations and methods used to overcome as-built construction limitations when installing EIFS on this particular structure for the purpose of improving energy efficiency. Energy consumption data collected during the year previous to, and the year following, the retrofit will be presented in a separate paper. Photographic documentation and as-built drawings for key EIFS features are included.