TN 71: Durability of building airtightness

Much progress has been made to improve the airtightness level of new buildings. Still, little is known about the durability of building airtightness, or the impact of degradation on airtightness. This report presents a comprehensive review of studies that deal with building airtightness durability. Regarding field measurement studies, the envelope airtightness seems to decrease during the first years after achievement and then stabilize. However, these variations are rarely explained. Key elements that may drive airtightness variations were identified. Regarding laboratory ageing studies, there is actually no standardized protocol to characterize the durability of product assemblies concerning airtightness. This report gives the pros and cons of various alternatives to define a protocol. Finally, this report stresses the importance of implementation conditions on airtightness durability, whose impact can be studied both on site and in laboratory.