Air Tightness Testing (Pressure / Leakage)

All new residential and commercial developments are required by Building Control to undergo Air Tightness Testing (also known as Air Pressure Testing (APT), Air Leakage Testing (ALT) and Air Permeability Testing (APT)). We offer a very competitive rate on our nationwide service for all types Air Tightness Testing.

The purpose of Air Tightness Testing is to assess the leakage (i.e. uncontrolled flow) of air through holes, cracks and gaps in the building fabric. Air leakage accounts for up to 40% of losses in the energy efficiency of a building. Benefits gained from increased insulation and more energy efficient boilers are quickly lost if the amount of uncontrolled air leaking out of the property is not effectively reduced. Uncontrolled leakage of air occurs through porous materials and at junctions between materials in the building fabric (i.e. doors, windows, walls, floors, ceilings, loft hatches and pipes etc).

The benefits of good Air Tightness in a building are numerous:

  • Heating bills reduced
  • CO2 emissions reduced
  • Illness and discomfort from cold draughts reduced
  • Noise ingress from outside reduced
  • Interstitial condensation reduced

The air test involves creating a difference of pressure between the inside and outside of a dwelling using a large fan fixed, air-tight to the door frame. The amount of air flow that is needed to generate a specific pressure differential then determines the amount of air leakage occurring through the building fabric. The flow rate is measured in terms of m3 per hour per m2 of building envelope area at a pressure difference of 50 Pascals.

If a test fails we can draw on our extensive construction knowledge to quickly identify the sources of the failure and provide remedial advice where possible to ensure that the test passes. Following the air pressure tests we will provide you with a professional report detailing the results. This is required by Building Control to assess the developments compliance with Part L of the Building Regulations.