Airtightness of sealed building joints: Comparison of performance before and after artificial ageing

Airtightness is considered an important factor on all levels of the building envelope, i.e. overall building envelope, on a component level and on a material level. Airtightness of the building envelope is a defining factor to achieve energy efficient and durable buildings, i.e. reduced risk of condensation and water infiltration through the building envelope, reduced risk of cold draughts and it improves the correct functioning of the HVAC-system. Over the past decades the amount of airtightness tests for newly built buildings in Belgium has significantly increased. However, the measured airtightness level of the tested buildings from 2006 to 2016 did not significantly change. This implies that there is still a lack of knowledge to achieve airtight building details, both on a design level and on the implementation of the building details. However, literature concerning airtightness of sealed building joints is very limited. In this study, the airtightness performance of different materials to seal building joints was experimentally assessed. In general, a good airtightness was achieved for all tested materials in case they were perfectly installed. However, the performance of the sealing materials was very sensitive to faulty workmanship and primarily depended on the quality of implementation, in particular for the tapes, silicone based materials and foam sealing strips. The performance of the liquid applied coating primarily depended on the characteristics of the materials and the application method was determining for the performance of the polyurethane foams.