Airtightness

Airtightness goes hand-in hand with a well-insulated building envelope and is the basis for a ’fabric first’ approach to designing low-energy buildings. Airtight buildings are comfortable environments free from unwanted draughts from gaps and cracks in the building fabric that cause heat loss and discomfort. Airtightness is achieved by good detailing and construction quality through the creation of a continuous air barrier with monolithic construction of airtight materials or with airtightness membranes and by taping all joints and by overlapping and taping membranes at junctions. To ensure good indoor air quality (IAQ), continuous, controlled background ventilaton is needed (e.g. MVHR) and careful specification of materials that do not offgas and cause health issues.