What is Airtightness?
Airtightness is the control of air leakage, i.e., the elimination of unwanted draughts through the external fabric of the building envelope. This may be achieved by the correct and proper installation of a vapour check or vapour barrier. Consequently condensation, mould, rot, damp and structural damage are also eliminated. This ensures a more viable structure, an insulation layer that can perform properly as it is now protected against penetrating moisture reducing the amount of energy-in-use in the building and CO2 emissions. While ventilation is intended, air leakage is not. It is desirable and necessary to have controlled ventilation for healthy comfortable buildings. A diagram showing a draughty leaky house, the red arrows highlight the potential airleakage pathsand the green arrows show intended ventilation/openings. A diagram showing a well sealed, well ventilated house. The key is to build tight and ventilate right.
