Construction in the public sector has led the charge for “going green” in recent years, with legislation at state, federal, and local levels dictating more efficient designs for government buildings. The utilization of building components like recycled materials and energy-efficient appliances get most of the attention, but systems that control airflow into and out of a structure are often overlooked, at least in the public eye, for reducing energy consumption. Oversight aside, buildings with tight air barriers tend to lose less heat during winter months, and don’t have to work as hard to maintain cool temperatures during summer months. In the heart of Virginia, Frederick County Public Schools had those benefits in mind when proposing additions for four elementary schools in the district.
The purpose of constructing an air barrier around a building is to basically wrap the building envelope with materials that have a low air permeance rating, which is to say materials that block air rather than facilitate its passage. Architects, like the one involved with the Winchester project, have numerous material choices when deciding on the air barrier system for a given structure. A combination of foam board and sealant is a popular option, and the district could have gone in that direction, but the process itself is labor-intensive. The utilization of closed-cell spray foam has been an increasingly popular option because it provides a single-application, single-material solution, which was
a contributing factor to the project’s architect specifying an SPF air barrier system for the new additions.