Building America Team: Building Envelope Materials

Partner: Massachusetts Clean Energy Center

Through this research, Building Envelope Materials developed a minimally invasive microinjection foam technology for retrofit insulation of enclosed roof cavities, such as cathedral ceilings, flat roofs, and dormer roofs.

A minimally invasive microinjection foam technology will allow for roof cavity retrofit insulation without removal of the ceiling surface or roof, greatly reducing the cost of the retrofit. 

Current practices for retrofit insulation of enclosed roof cavities are highly invasive, requiring removal of the ceiling surface or the roof. This novel process will not require removal of the ceiling surface or roof, greatly reducing the cost of the retrofit. The team will develop and validate this technology by:

  • Injecting closed cell polyurethane insulating foam into ceiling surfaces through a tiny hole
  • Using narrow diameter tubes, precisely placing foam where needed in cavities
  • Developing a novel procedure for injecting the appropriate amount of material
  • Developing dispense equipment to communicate with technician and validate quality
  • Using an infrared camera to validate fill quality.

The team has successfully completed their second pilot project, which included injecting a fiberglass-filled cathedral ceiling and validating the installation quality through infrared (IR) imaging. In the next budget period, the team will optimize the process by using more consistent fill around the rafter vent and eliminating the need for soffit lining. 

Image of an air-sealing technology for enclosed roof cavities.

Results so far:

  • Average foam thickness of 3.9” achieved, far surpassing 2” target
  • R-30 value achieved, surpassing R-13 target
  • Permeance <1 achieved
  • No significant delamination
  • No observable air gaps and a minimum thickness of 2.5”.

Remaining work:

  • Develop methods for more consistent fill around rafter vents
  • Develop strategy to prevent foam spillage into soffit without need for soffit liners
  • Develop application for pourable foam to be used in flat roof applications.


For more information, project presentations, and related publications, visit the Validation Study of Experimental Insulating and Air-Sealing Technology for Enclosed Roof Cavities webpage