Air Tightness Testing

Operating nationwide Rega Ventilation offer air tightness tests for domestic properties and are ATTMA accredited. We specialise in the self-build market having worked closely with self-builders for over 30 years and are able to provide advice and support throughout the process.

Why do I need an air tightness test?

All new build domestic properties require an air tightness test to conform with Building Regulations Part L1A. The test is carried out to ensure that the build has been completed with minimal air leakage and that it meets calculated design air permeability (DAP) which is part of the SAP calculations. This will in turn help to reduce energy usage of the property as well as reducing overall heating costs.


How do I prepare for the test?

Before the air tightness test is carried out the build must be virtually complete and there are a few key assurances to be made prior to the test:

  • Loft hatches fitted
  • Any perforations through the walls and floors should be sealed.
  • All traps in bathrooms/wet areas should be filled with water.
  • Skirting boards should be fitted in all areas and sealed to the floor.
  • All electrical installation must be completed with sockets and switch plates fitted and mains power on.

What happens during an air test?

When our engineers arrive on site the first step is to carry out an inspection of the property to verify that all the requirements for a successful test have been met. This will include a brief visual check of seals around pipes etc. and checking all windows and external doors are closed and trickle vents are closed if present. It is also required that an external wind speed check be carried out by our testing engineers, as the test is not permitted to be carried out in adverse weather conditions.

The next stage would be to seal external openings as necessary such as MVHR vents, extract fans, chimney flues or passive ventilation.

Once the preparations have been made a fan will be fitted to the front door of the property for the test to begin. It is not essential for tradesmen to leave the building during the test, but it is imperative that all external windows and doors remain closed throughout the test.

If any issues arise during the testing, our engineers will work alongside you to identify any possible causes using smoke testing equipment to locate leakage paths and will provide advice on how to rectify.

What do we need from you?

In order to carry out an air test we will need scale drawings including plans and sections of the dwelling; which will allow us to calculate the building envelope area, along with a copy of the SAP calculations showing the design air permeability.

Contact us for more information or a quotation.

...for a fresher, healthier, home

Rega Ventilation Limited

21/22 Eldon Way, Biggleswade,
Beds SG18 8NH


Rega Ventilation Limited 21/22 Eldon Way, Biggleswade, Beds SG18 8NH