An airtight building can help save energy and reduce energy bills. Airtightness is a measure of the amount of uncontrolled air leaking through the fabric of a building. It is one of the most significant factors in inefficiently heated buildings. Studies have confirmed that poor airtightness can account for 40% heat loss in modern buildings! Warm, damp air leaking into the fabric of the house can also lead to increased risk of condensation which in turn can lead to insulation and structural degradation.

Key for many builders and self-builders is considering airtightness in the early stages of the design and build process. The air barrier must be designed into the building at the initial design stage.

With the need to control air leakage as defined in Approved Document L of the Building Regulations, Taylor Lane (Wales) can offer advice and services to help you achieve your airtightness requirements. We have a range of wall types and processes to fulfil both the thermal and airtightness levels your energy assessor has designed into the building’s Standard Assessment Procedure (SAP) calculation.

Building Regulations (for England and Wales, and Northern Ireland) currently set a reasonable limit for airtightness of 10m3/h/m2 at 50Pa but good practice is 5m3/h/m2, and best practice, 3m3/h/m2. Taylor Lane (Wales) can exceed this, if required. We have achieved a Stage 1 airtightness level of 0.5m3/h/m2 for a development that was built to the Passivhaus standard.

While the airtightness layer will not ensure that the U-Values are achieved, it will increase thermal performance.

In conjunction with an experienced service partner, air testing can be offered at various stages of the build, providing you with the reassurance that you are on target to achieve your objectives.  This takes place before other trades have reached a stage that could result in difficult and expensive remedial work.  Tests, reports and certificates can be issued at various stages of the build, including completion compliance.  Once the build is finished, the final pressure test will generate the certificate for submission to the Energy Assessor and/or Building Control.


Taylor Lane (Wales) can adopt a Passivhaus approach for clients wishing to achieve or emulate the global standard.

Originating in Germany, the Passivhaus standard recognises and embraces thermal performance, airtightness and ventilation.  Over 30,000 houses worldwide have been built to this standard.

A Passivhaus results in an ultra-low energy use house that requires little energy for space heating or cooling. Offices, schools and even commercial buildings are benefiting from the principles of Passivhaus.  A Passivhaus is a truly efficient home, offering long-term affordability and ecological benefits.

Airtightness is key to the design process and high levels of insulation are vital to achieving the Passivhaus standard .  Passivhaus requires a continuous thermal envelope, with no weak points – eliminating cold spots and heat loss; this means thermal bridge free construction.

Catg Catg Chas PEFC Constructionline

Timber Frame STA catg STA Gold