As a UKAS & ATTMA Level 2 accredited air testing company, we have undertaken thousands of air tightness test over the last 20 years and despite an overall improvement most air tightness results, there is still room for improvement.

Preparing for your air tightness test

With this in-mind we have written the following article to help client prepare for their air tightness test. There are literally hundreds of areas that need to be considered when trying to create an airtight building – the main areas are:

1. The building fabric: the building fabric accounts for the walls, floor and roof. The type of build will dictate the amount of extra ‘onsite’ sealing works that may be required. For instance, it’s usually easier building with timber frame, than with masonry.
2. Wall/floor/ceiling junctions: It is usually the wall/floor junction around skirting boards, and the wall/roof junctions by the eaves where the problems are usually worst.
3. Doors and windows: doors and windows are often some of the worst areas of air leakage within a building fabric. Where the frame meets the wall reveal, is usually down to site detailing, but how the window or door closes against the frame is down to the window/door manufacturer and their installers. Sash windows or sliding patio doors can be susceptible to air leakage even if they are working properly. Twisted frames, missing seals and poorly (loosely) adjusted latches, are just a few issues that we find during smoke testing.
4. M&E Service penetrations: service penetrations through the building envelope to allow for cables, pipes and ductwork are also a main area of air leakage. They’re not difficult to deal with if tackled at the right juncture i.e., before kitchen units are installed, and it is largely a matter of site supervision that they found and dealt with by a dedicated sealing team of an air tightness champion.
5. Internal pocket doors – internal pocket doors, such as the type installed between living/dining rooms and bathrooms, can be a massive area of air leakage, so it’s really important that the builder builds an airtight pocket (sleeve) for the door prior to installing the running gear for the doors, and finally boxing out.
6. Recessed ceiling lights – recessed ceiling lights in kitchens/living rooms etc. can also be large area of air leakage. In some large living areas, we have counted over 100 ceiling lights, with each light leaking the accumulated air loss can be huge. Many manufacturers provide airtight (fireproof) socks that go over the light housing (within the ceiling void) which can be an effective solution.
7. Ceiling hatches – ceiling hatches, can also leak large amounts of air. Some manufactures offer proprietary door and frame systems, which are easier to install and will further reduce air leakage.
8. Loft cupboards – the areas behind loft cupboards doors are often unsealed, sometimes there isn’t even flooring installed. it is essential that the walls ceiling and floors are completely finished, and the cupboard door are fully sealed with good quality seals.

At the start of your design and build process, your architect should be specifying what needs to be done in regard to air tightness, and the importance of having an air tightness champion on site to reduce the chance of an air tightness test failure.

We can help you pass your air tightness test

We work with our customers throughout their design and construction stages, we can provide advice and guidance on the most feasible ways to avoid air leakage and pass your air tightness test. we have also written the following air tightness checklist to help clients prepare for their testing.

We can provide general air leakage design advice for your building envelope and onsite guidance. Upon completion of your project, we provide Nationwide UKAS Accredited Tightness Testing for domestic and commercial buildings to help you demonstrate Building Regulation Part L Compliance.

To find out more about our air tightness testing service or if you wish to discuss your project, please contact us by email at info@aptoundtesting.co.uk or visit our website