British Building Regulations require improved air-tightness of a building which is important for the energy efficiency.
Does air-tightness not contradict the claim of breathability?
Not at all – when talking about air-tightness we speak about avoiding air leakages, for instance by providing high quality windows and properly sealed openings to the outside such as vents,
outside lights and taps.
Amongst other, the skilful sealing of openings for electricity cables and water pipes is important, as well as the correctly sealed connections of walls and windows. Stommel Haus homes are
typically 3 times and more air tight than British Building Regulations require with values of <1.0 m3/(m2.hr)@50Pa.