The air and wind tight building envelope can be compared with the clothing of people. In cold and damp weather several layers of clothes prove their value ("onion principle").


On the skin you wear functional underwear to carry sweat away from the skin. This corresponds to the airtight building envelope formed by the base plaster on the masonry or the breathable mebrane on the stud walls and the vapour control layer in the roof. It is required by the Building Regulations  of the UK, Irland and German as energy saving regulation (EnEV) and can be easily tested by a blower-door test.


A woolly sweater protects from cold (= insulation). But in cold, windy weather this sweater is not sufficient; you additionally need a wind tight jacket (= facade membrane or breathable membrane). When this jacket is open, cold wind and moist air enter the sweater and you feel cold. If it is, however, closed, which corresponds to the windtight building envelope, wind and weather are kept out and the body remains comfortably warm. This layer is formed by the roofing tiles and the permanently sealed breathable membranes.


More than half of the warm or cool air escapes through leaking areas in an average  building  in Australia. Consequently an air and wind tight layer is the most reliable protection against exsessive energy and heating/cooling costs! Regular, controlled ventilation or a energy recovering ventilation system provide for healthy indoor air.


In addition, the air and wind tight building envelope fulfills further important functions:

The insulation is protected from damage by mould, which would lead to expensive renovation work and health hazards! 

It prevents draught and increases the living comfort! 

You can do without toxic wood preservatives and keep the construction free from vermin!  

It locks out odours, noise and summer heat! 

It increases the value of your building! 


SIGA high-performance adhesives offer first-class quality. With the easy to apply SIGA system you create an air and wind tight layer which offers you the best reliability and comfort throughout the entire life of your house. Our word for it!