When devising the details and planning for air barrier continuity, and indeed continuity of all critical barriers, it is important to consider the following key constructibility and sequencing issues:
- Use approaches that allow for common construction sequencing (e.g., formwork, concrete, framing, cladding etc.), and separate the air barrier transition work from the various other phases such as framing wherever possible.
- Use "inspectable" approaches that don't rely on blind seals behind framing members or finishes. Direct-applied membranes, tapes and sealants are easier to inspect and make airtight compared to concealed gaskets or spray foam applications.
- Keep it details as simple as possible, using construction materials and techniques that are accessible and straightforward. Where possible, keep the building shape simple to minimize intersections, especially roof-to-wall interfaces.
Careful consideration and attention to detail is required to ensure a continuous air barrier between assemblies, penetrations, and building components. This is important because each is part of the air barrier system, which should provide a durable and continuous air barrier across the entire building enclosure. Common deficiencies and challenging areas for exterior air barrier installation can occur at all areas of the air barrier system. The integrity of the air barrier relies upon the quality and completeness of the installation work. During construction, ensure the detailing work is reviewed and tracked by a dedicated site attendant. Tracking issues and potential deficiencies is one of the best way to improve overall building airtightness and correct detailing. Some common air barrier challenges and likely deficiency locations include:
- Structural and service wall penetrations using sealant and membranes
- Wrinkled/fish-mouth/incomplete membrane laps
- Roof-to-wall and other interfaces where various transition materials are used
- Roof/ceiling penetrations
- Window membrane and perimeter sealing
- Interior ceiling penetrations and partition walls at an interior air barrier
- Above-grade to below-grade transitions
- Complex building forms and enclosure shapes such as fin walls and projections