Extended Plate & Beam Construction Guide

Extended Plate and Beam (EP&B) is an advanced wall system developed by Home Innovation Research Labs as part of the Building America Research Program. This innovative configuration has been tested in the lab and in four different demonstration buildings in climate zones 4, 5, and 6.

EP&B is based on tried-and-true lumber construction methodologies, integrating rigid foam sheathing with standard framing practices into a system that preserves many conventional construction features and minimizes builder risk. The EP&B wall system is composed of familiar wall materials but in a different configuration:

  • 2x4 studs, with top and bottom plate extensions of 2x6
  • 2-in. continuous insulation (c.i.) exterior to the wall cavity, interior to the wood structure panel (WSP)
  • More than 95% of the wall area free of thermal bridging
  • Common methods and materials for framing, air-sealing, insulation, drainage plane and siding attachment
  • Double rim board (beam) that is also a header and is inset to provide space for a c.i. thermal break

This guide contains all the information you need to build a high-performing wall at reasonable cost and effort that meets or exceeds energy code prescriptive insulation requirements for all U.S. climate zones.