Protection against mould and heat losses – Airtight building is required by law in many territories
Building regulations and standards demand airtight constructions for a good reason: after all, the airtightness layer helps to save energy, avoid moisture damage to structures, and also prevent unpleasantly warm indoor temperatures in summer.
Thermal insulation decouples the indoor climate from the outdoor climate. The temperature difference between these two climate zones tries to even itself out by means of air flow, also known as convection. In wintertime, this involves warm air from inside the building exiting through the structure into exterior surroundings. The airtightness layer prevents this air flow and thus also hinders the loss of warm air to the outside. At the same time, this layer helps to ensure that mould and moisture damage to building structures due to condensation are avoided, and also provides for a pleasant indoor climate in summertime.
Airtightness in buildings - Blower door testing in Australia