Air Tightness relates to the loss of air from inside a building to the outside and vice versa. Good air tightness is vital in an energy efficient build, as in some homes with poor air tightness it can result in up to 40% of heat loss.
Air Tightness Testing is a requirement for all new builds. The test involves sealing of all trickle vents and sources of designed ventilation, before using a large door mounted fan to de-pressurise the building. The rate that the air escapes is then measured and a rating is determined taking into account the size and volume of the building against a benchmark.
The ideal insulation structure in a building involves 3 layers:
An airproofing layer, for example a vapour retarder, is positioned on the side of the insulation facing the room
The insulation is in the middle.
On the exterior side, a wind barrier such as an underlay or wall lining membrane covers the insulation
This design ensures that weather, condensation, mould and air flow do not negatively affect the performance of the building component or even cause structural damage.
There are ways to reduce the amount of air leakage in a dwelling by:
Sealing gaps and cracks
Using joist seals
Using Pro Clima Solitex Plus moisture-variable and vapour retarding and airtightness membranes
When undertaking a retrofit project plan your air tightness approach at the start
Allow wires and cables to pass through a Pro Clima Roflex
Seal up all joints between walls and floors with air tightness tape