Building America Team: Home Innovation Research Labs

Partners: McIntyre Builders Inc, Dow Building Solutions, Milgard Windows & Doors, National Association of Home Builders, Lennar Corporation, Pella, BRINC Building Products, Inc., Rmax, Owens Corning, JELD-WEN, American Chemistry Council, American Architectural Manufacturers Association, and Window and Door Manufacturers Association

Three men standing behind an insulation window.

The goal of this research effort is to develop performance data on full-scale laboratory testing and establish applicability boundaries for conventional installation methods in which the window is installed directly over foam sheathing. The focus is on capturing performance of a broad range of window and foam sheathing installation configurations. Variables include window type, window weight, foam material, foam sheathing thickness, and more. The results of the study will validate and demonstrate performance of windows, provide window installation specifications, and enable changes to provisions of applicable codes and standards.

Overly complicated details and solutions with added cost and on-site labor present a major barrier for builders attempting to integrate energy-efficiency features into their construction practices. This project will use objective performance data measured through full-scale testing to develop solutions optimized across broad metrics, including structural capacity, deformation, constructability, and cost. In a broader perspective, the project seeks technologies that minimize disruption and reduce the cost implications associated with adding exterior foam insulation to the wall assembly. The results will be equally applicable to new construction and retrofits.

Recent results:

Comparing a range of performance data from window and foam sheathing installation methods will help identify technologies that minimize disruption and reduce costs during installation.

  • First water penetration test: bubbling at sill, drains when pressure is removed
  • Temperature cycling: no issues
  • Service condition wind loading: no issues
  • Second water penetration test: bubbling at sill, drains when pressure is removed
  • Vertical displacement monitoring: average range of movement 0.025 inches
  • Third water penetration test: bubbling at sill, drains when pressure is removed
  • Post-structural wind loading: window sash pops out.

Remaining work:

Four windows with insulation pipes attached.
  • Complete last 25% of testing
  • Evaluate results against established performance criteria
  • Make recommendations based on performance
  • Propose construction solutions and limitations
  • Provide test results to support development of installation practices
  • Support development of standardized testing of similar assembles. 


For more information, project presentations, and related publications, visit the Structural Performance of Windows in Walls with Continuous Insulation webpage.