President, French Engineering, Inc., Houston, Texas
Pages: 18 Published: Jan 1999
A high-rise apartment project located in Minneapolis, Minnesota was originally constructed in the 1970's with site-fabricated concrete spandrel panels and column covers. Due to structural concerns, panel cracking and water leakage problems, the building was retrofitted with a polymer modified (PM) Exterior Insulation and Finish System (EIFS) in 1984. Within a few years, noticeable cracks had developed and significant changes in the cladding appearance became manifest. Extensive investigation and analysis revealed specific material defects that were particular to the EIFS manufacturer, as well as poor detailing and improper workmanship related to several key areas of the building envelope. The EIFS wall cladding suffered progressive deterioration until early in 1993, when a severe wind storm removed a section of the cladding from an upper floor at one end of the building. Renovation of the exterior cladding involved utilization of specific design concepts developed in response to the experience of this author pertaining to numerous investigations of poorly performing wall systems. Retrofit application of the new PB EIFS utilized several innovative details developed for the renovation of this building, including special details required around the 960 punched windows of this 21 story, multi-family, residential facility. Specifications for the retrofit work stipulated use of PB EIFS materials, mix proportions and application methods, which based on the latest research and field experience, will produce the highest degree of success in achieving a cladding system that is as long-lasting and serviceable as possible. In addition, exterior sheathing materials used as a substrate for the EIFS at this project were composed of new, silicone-treated, glass-fiber-faced, gypsum board.
Exterior Insulation and Finish System, EIFS, retrofit, cladding, highrise, design, details, moisture-resistant gypsum sheathing, two-stage sealants, alkali attack, prefabricated components
Paper ID: STP13330S