Exterior Continuous Insulation and the Positive Impact on Building Envelope Performance— Achieving New Energy Code Wall Insulation Metrics

Abstract

Where the goals of high-performance buildings create a demand for high-performance wall assemblies, the use and proper integration of continuous insulation (CI) and continuous air barriers has never been of greater consequence. This paper focuses on the integration of exterior CI through new model building energy code requirements for framed wall insulation specifically related to mandated improved energy efficiency objectives. Architects, engineers, contractors, developers, building owners, and facility managers must become better educated on building code requirements, improved energy efficiency strategies, and the positive attributes associated with exterior CI. Regional design and climate influences are significant when developing an energy-efficient wall assembly, and model building codes take no exception by stipulating insulation strategies and design values for framed wall assemblies in the eight U.S. climate zones based on adopted energy code criteria. There is a succinct relationship among overall building envelope performance, wall assembly design, and insulation type and placement. The mandated and proper integration of exterior CI along with integration of continuous air barriers in framed wall construction become increasingly important to understand, especially for national prototype projects that cross these many different climate zone areas. To this end, this paper outlines recent changes to model energy codes for insulation requirements in framed wall assemblies as well as explores strategies, options, and related challenges for implementation of exterior CI into framed wall design. This paper further conveys the positive attributes of exterior CI and the overall improvements to building envelope performance based on measurements of managed construction cost, improved energy efficiency/reduced energy consumption, and lowered environmental impact over the life of the building structure.