Towards Airtightness – The Contractor’s Role in Designing and Constructing the Air Barrier System

The design and construction of a continuous air barrier system at the building enclosure is fundamental to the creation of high performance buildings – buildings that are durable and energy efficient while providing a comfortable and healthy indoor environment for living and working. However, it is fair to say that implementing air barrier systems is “easier said than done.” Cost effectiveness, communication of design intent, constructability, coordination of trades, and material compatibility are just a few of the issues that come into play on projects that attempt to incorporate whole building air barrier systems.

This paper will discuss the contractor’s role in the commissioning process that is intended to deliver effective air barrier systems on large multi-unit residential buildings in the Pacific Northwest.2 The paper will be presented from one general contractor’s perspective. Among the specific topics discussed are: 1) understanding the design of the air barrier from materials to assembly to system, 2) the importance – and challenges – of coordinating the design team and construction team efforts, 3) the need for clearly developed design detailing and specifications to document the air barrier requirements, and 4) the testing process – planning for it and knowing what to expect.

Case studies of commissioning process implementation on several large multi-unit residential projects will be used to illustrate the ideas and concepts discussed in the paper including a review of newly implemented code requirements for air barriers and testing performance.