A new aerosol sealing technology has been developed for automated house envelope sealing. The process involves pressurizing the house while applying an aerosol sealant "fog" to the house interior. The project team worked directly with builders in California and Minnesota to identify the best stages for incorporating aerosol sealing with regard to cost, performance, and seamless integration into the construction process. One group of California builders used sealed attic construction with the first four houses, using spray foam under the roof deck for insulation and air sealing. Two houses that were aerosol sealed before spray foam had a leakage of 1.8 ACH50 prior to the application of spray foam. This indicates that the air sealing benefit of spray foam is not necessary when aerosol sealing is applied. When construction was complete, the four aerosol-sealed houses had an average tightness of 1.1 ACH50, which was 39% tighter than similar control houses. Two other houses with box-netted insulation had an average tightness of 3.0 ACH50 after aerosol sealing and prior to drywall. A total of 13 of the 15 houses in Minnesota were sealed prior to drywall installation. They had an average tightness of 0.81 ACH50, and four were tighter than the passive house standard of 0.6 ACH50. At the end of construction, the average tightness for the first builder was 0.88 ACH50, which was 34% tighter than similar control houses.
Citation: Thermal Buildings XIV 2019