Airtightness of a multi-family passive residential building in the Czech Republic

During the construction of a multi-family residential building the developer decided that the building must comply with the airtightness requirements for passive houses. Based on inspection work and preliminary testing, the original design was revised. The execution of the new air barrier system was supervised. Selected flats were repeatedly tested during the construction process. The whole building was tested once before the completion of the construction. After the completion of the building, all the flats, the whole building and the staircase were tested again. In order to evaluate the effectiveness of the designed air barrier system, a very similar “standard” building of the same development was tested under the same conditions. The airtightness deteriorated during the building process, which proves the need of control until the completion of the building. The test results of particular flats were worse than the whole building test results due to the internal leakage (it points out the limits of sampling methods). The estimation of the airtightness of different envelope sections allowed the major leakages to be identified, despite a significant uncertainty. The experience proved that the major problems can be avoided in the early stages of the design process.