Aerosol Sealing of Building Envelopes

PROBLEM

Air leaks in buildings waste energy and can cause moisture and indoor air quality problems. Current methods for tightening building shells have relied primarily on manual sealing methods that are labor intensive and often insufficient. We are testing an aerosol envelope sealing process, AeroBarrier—that was developed at UC Davis—to improve sealing effectiveness, reduce labor costs, and improve contractor installation consistency.

SOLUTION

AeroBarrier involves pressurizing a building while applying an aerosol “fog” to the interior. As the air escapes through leaks in the shell of the building, the aerosolized sealant is transported to the leaks, and seals them as the particles try to escape from the building.


GOAL AND RESULTS

2019

One project, funded by the Department of Energy, is evaluating the labor and material costs and energy efficiency performance of AeroBarrier applied at different stages of the new construction process.

Another project, funded by the California Energy Commission, is evaluating the indoor air quality and energy efficiency performance of AeroBarrier as a retrofit to existing homes.

This past year, we demonstrated AeroBarrier in both new and existing single-family homes in California. Sealing new homes took place during different stages of construction and with different insulation methods, including rough-in (before and after spray foam insulation, before blow-in insulation) and after drywall. Two existing homes were also sealed as part of a retrofit package aimed at improving energy efficiency and indoor air quality.

  • The entire preparation, sealing and clean up process took 4-7 hours in new construction and 22 hours in existing homes. Of this time, 1-3 hours was spent sealing in each home.
  • New construction homes achieved at least 50% reduction in air leakage after sealing, with 9 of the 11 homes achieving over 70% reduction.
  • Existing homes achieved between 37% and 64% reduction in leakage.
  • Considering the level of air tightness achieved with AeroBarrier and the amount of effort currently employed to reduce air leakage, it is likely that other manual sealing efforts could be eliminated saving on cost of construction, while also achieving superior and more consistent air tightness.


2018 and Earlier

Retrofit of Buildings at Military Facilities

We performed retrofit sealing work for a project funded by the Department of Defense (DoD) ESTCP program. The objective was to validate AeroBarrier as a cost-effective means to meet U.S. Army Corps of Engineers’ tightness requirements for military facilities. Researchers sealed various building types, in varied climates, to evaluate the ability of the technology to be applied on a large scale. WCEC also conducted lab testing of seal durability and modeled the impact tighter envelopes have on energy use in these facilities.
Seals could withstand 5,000 Pa of pressure.

Researchers found that AeroBarrier is very effective at sealing building leaks on DoD facilities. Ultimately, over 75,000 CFM at 75 Pa of building pressurization was sealed over sixteen demonstrations, cutting the average air leakage of the buildings in half.

New Single-Family Homes Demonstration

We demonstrated that AeroBarrier sealed 79% of leaks in single-family homes through a project funded by the Department of Energy’s Building America program. The aerosol process also sealed homes 56% tighter than the homes sealed with conventional open-cell spray foam, allowing the builder the flexibility to choose more cost-effective fiberglass insulation material.

The sealing process required access to the home for about four hours with 1-3 hours of actual sealing time.

Considering the level of air tightness achieved with AeroBarrier and the amount of effort currently employed to reduce air leakage in homes, it is likely that other manual sealing efforts could be eliminated saving on cost of construction, while also achieving superior and more consistent envelope tightness.

Contact the Project Manager

wcec@ucdavis.edu