Panels, Perfect Walls, and Prefabrication: High Performance Enclosure Retrofits

Abstract

65% of buildings that will exist in 2040 are already standing. Of these, a substantial number were built before the advent of modern energy codes. These are likely to have enclosure designs that are not capable of high energy performance due to inadequate insulation and excessive air leakage. Many of these buildings also suffer from durability issues, either to exterior finishes or the structural components of the wall. These issues can be remedied through the application of a carefully considered exterior insulation retrofit. Historically, these retrofits are carried out using highly customized processes that are slow and prohibitively expensive.

Fourteen wall insulation upgrade techniques were studied at a cold climate research facility in ASHRAE Climate Zone 7 for two years. Comprehensive experimental data, taken using over 700 sensors, were used to calibrate energy and hygrothermal models for extrapolation to other climates. Preliminary cost data were also gathered. One of these techniques, known as the Overcoat Panel System (OPS), has been further developed. The panel is intended to be prefabricated in a factory, and simply hung on candidate buildings. The panel design observes “Perfect Wall” principles of control layer sequencing. Another method in the original study, using proprietary EPS foam panels with an integrated cladding attachment component, is now being deployed in a field study in Minnesota. This paper will summarize the findings of the original study and present the OPS and EPS systems and preliminary findings from its application in Minnesota.