Air tightness of apartments before and after renovation.

This study aimed to research the airtightness of the building envelope in apartments before and after renovation. Measurements were carried out in three apartment buildings. One to four apartments were examined in each building. Typical renovation measures included changing the windows and refurbishing the interior surfaces. In some cases the ventilation system was renovated as well. No special emphasis was placed on the sealing of the envelope. The airtightness of the apartments increased in most cases. There were, however, apartments that became leakier during the renovation. Poor workmanship was usually evident in these cases. The main leakage route in the measured apartments seemed to be the balcony door.