Air tightness project guide

Why is it important?

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.

Hints & Tips

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