Air leakages have an increasing impact on the overall energy performance of new buildings. Therefore, since the early 2000’s, regulations in many countries explicitly account for airtightness, sometimes with mandatory requirements, as a consequence of Europe’s ambition to generalize nearly zero energy buildings by 2030. However, having a requirement on building airtightness is relevant only if the airtightness level is durable. Nevertheless, studies have shown that a mandatory level of airtightness leads to last-minute taping and mastic setting that is most probably not durable.

The durability of airtightness products and assemblies at mid- and long-term scales is, therefore, a pending question. Indeed, this subject remains very complex, since it covers in the meantime:

• the modelling of the mechanisms of buildings’ and products’ loads and deformations,
• the accelerated ageing in laboratory-controlled conditions and,
• the performance characterization from field measurements results.

In the past years, several studies have focused on this issue using two different approaches. Some studies seek to characterize the evolution over time of the airtightness by field measurements in real buildings. The other studies are based on laboratory measurements in order to test the accelerated ageing of airtightness products.