At what point in the build am I ready for an air test?

16 August 2018 Kingspan Timber Solutions

How to prepare for an air test

Man carrying out airtightness test
It’s essential that your building is well prepared for when the air tester arrives on site. Remember you are likely to incur abortive fees if the tester arrives and your home is not ready.
That means the external envelope is complete (i.e. ensure all external windows, doors and trickle vents are closed), internals completed to decoration, second fix plumbing and electrical works completed, all penetrations through into ducts/boxings and external walls to be suitably sealed, all sanitary ware traps to be filled with water.

You won’t be able to do work in the dwelling at the time of tests.

What are the common air leakage areas?



Most kitchens have skirting fitted but few have it fitted behind kitchen units. Fitting skirting behind units may seem to be a waste and may make fitting the kitchen units, particularly integrated appliances, more difficult but it can dramatically increase the air tightness of the kitchen if the skirting is sealed top and bottom. Sink wastes should be ‘cored’ through and sealed before units are fitted.
Boiler exhausts/vents should be sealed, along with water pipes, particularly where they are fitted through the ceiling.


In line with the principles above for kitchens, skirting should be fitted behind baths where possible. Bath/sink and toilet wastes should be sealed along with the water supply pipes.

In some instances ‘traps’ fitted beneath baths and specifically shower trays are ‘cut’ in to the floor to allow for their physical size and to make fitting easier. The cutting away of sections of flooring for this purpose causes serious air leakage and should be avoided where ever possible. Bath and shower panels should be fitted and sealed.

Other general areas

Radiator pipes should be sealed where they emerge from the floor but more importantly where flexible piping is used and fitted through the plasterboard behind the radiators. Proprietary fittings should be used and additionally sealed if ill-fitting. Skirting to all rooms should be sealed top and bottom, including skirting to internal walls. Trickle vents should be closed prior to attendance of air tester.

What are the common air leakage areas?

Man carrying out airtightness test

The top 14 most common points of air leakage in a home are as follow:

1. Floors - this includes timber and concrete beam and block suspended floors - ventilation grills, underfloor heating systems, gaps found around the perimeter, large gaps around pipes that go through the wall etc.
2. Floorboards or blocks - service pipes etc.

3. Windows and doors - incorrectly fitting units that leave gaps

4. Areas that go through walls, such as joists or services

5. Window sills and reveals - gaps around the casements etc.

6. Holes or gaps between platerboard dry linings and ceilings

7. Partition walls (internally)

8. Loft hatches/access - poorly sealed units that leave gaps

9. Recessed lights within the ceiling and/or ceiling roses

10. Soil and vent pipes (including flue stacks)

11. Extractor fans (including cooker hoods)

12. Service pipes (including waste pipes, cables etc.)

13. Leakage through walls in general

14. Gaps between external walls and solid build floors