Wolf Bracke, Nathan Van Den Bossche, Arnold Janssens
Bibliographic info:
35th AIVC Conference " Ventilation and airtightness in transforming the building stock to high performance", Poznań, Poland, 24-25 September 2014

During field measurements on the airtightness of passive houses, ventilations system’s roof penetrations showed to be one of the major leakage paths, as they were not sealed using the appropriate, durable techniques. Therefore, a series of laboratory measurements was conducted on wood-frame walls to study different air sealing solutions. The use of special airtight gaskets is compared to less advanced sealing methods such as sprayed polyurethane foam and the use of pieces of tape.

The airtightness of different solutions is tested on two different test setups at the Test Centre for Façade Elements, Ghent University. One large-scale setup, designed to measure the air leakage rate of windows, was used and an additional smaller-scale test setup was built. For both setups, measurement principle, test setup and results are reported.

As workmanship quality is an essential aspect for achieving airtight building connections, the repeatability of the sealing methods was addressed by installing multiple identical setups. The quality was reviewed with the use of a smoke generator and the samples were subjected to multiple water tightness tests under static and pulsating pressure. To evaluate the durability of the different solutions, the impact of the water tightness tests is discussed.

A classification for the airtightness of building penetrations is reviewed together with the impact of the air leakage through building penetrations on the overall air leakage of buildings. In the laboratory, all tested solutions could be classified in the best airtightness classification, though large differences between executions methods were evident. The use of standard, rigid airtightness tape is not recommended for sealing 3-dimensional connections such as building penetrations, and is not regarded as a durable sealing method. However, specific flexible tapes are on the market which perform very well and sprayed PUR also showed excellent results when executed correctly. EPDM gaskets showed a higher leakage than flexible tape and PUR, but are also a very good choice. The adaptability of the penetration is a great advantage regarding the durability of the connection.