Home Innovation Research Labs studied the extended plate and beam (EP&B) wall system during a two-year period from mid-2015 to mid-2017 to determine the wall’s structural performance, moisture durability, constructability, and cost effectiveness for use as a high-R enclosure system for energy code minimum and above-code performance in climate zones 4–8.
This research was intended to explore the structural, thermal, and moisture performance of a wall that can be readily adopted by the large cohort of traditional builders who have previously resisted the switch to a high-R wall. Despite many years of development, structural insulated panels, insulated concrete forms, and double wall construction command a small market share of residential wall systems, which is largely because of atypical materials, methods, and details that require retooling and retraining. Use of 2x6 framing provides deeper stud cavities for more insulation, but the maximum thermal performance of the wall is effectively limited to 2015 International Energy Conservation Code (IECC) targets for climate zones 3–5, and the temperature profile across the wall subjects the cavity to moisture condensation risk in colder climates.