The Main Air Leakage Paths in Dwellings

With the air tightness target being halved from the old standard of 10m3/hr/m2 to 5m3/hr/m2 on most new projects it is essential that the all air leakage paths are sealed prior to the air tightness test. In our experience another reasons for air tightness testing failures is down to a general lack of understanding where the air seal line is on site, as well as poor quality control of Robust Details and a lack of adequate air tightness experience.

Air Leakage in Dwellings

The most common areas of air leakage in flats

However let’s try not to panic, some relatively simple measures and procedures could be adopted by the developers that would address a number of these leakage paths. Such measures would include:
Sealing all visible and hidden service penetrations in the following areas:

Services Penetrations

  • Service penetration’s around boilers pipes.
  • Service penetration’s around under floor heating.
  • Service penetrations in the kitchen and utility room.
  • Service penetrations in the toilets, bathroom and en-suite.
  • Pipework penetrations behind the radiators.
  • Service penetrations in the bathrooms and en-suite.
  • Around electrical fuse box.
  • Around extract fans.

General Air Leakage Paths

  • Gaps between skirting board and floor on each floor level.
  • Behind kitchen units.
  • Behind Utility Cupboards
  • Around poorly fitted trickle vents.
  • Around Patio doors.
  • Gaps around the stairs.
  • Around loft hatch.
  • Gaps around the bath panel and the shower tray.

If you need to prepare your building for an air tightness test please review our Air Tightness checklist.

If you would like more information in regards to our air tightness testing and consultancy services then please contact us at