Ceilings where no particular attention has been paid to securing the airtightness of the ceiling. No attempt is made to fill hidden cracks (in cupboards, behind kitchen units, etc.) and penetrations through the ceiling by cables and pipes.
Typically the airtightness of buildings in the UK have been measured at about 12 to 14m3 / m2 / hr. The target figure for the UK is 10 m3 / m2 /hr, whereas, the rest of Europe are achieving 3 to 5 m3 / m2 / hr.
