Air Tightness Testing – Persimmon Homes

We were appointed by Persimmon Homes to deliver air tightness tests across their new developments in the North West. The developments consist of 3-5 bedroom house types. Air tightness testing is a crucial phase of any build as the result will significantly affect the energy performance of the building and if not completed in a timely manner can delay the CML process.



Persimmon Homes


Air Tightness Testing


Various North West Persimmon developments 

How long

2018- ongoing


The current building regulations require the new build properties achieve the target air test value set within the SAP Calculation. This is the air leakage rate per hour, per square meter of envelope area. To make sure the property passes first time, we worked with the Persimmon site team to make sure all envelope components, including doors, windows, hatches, sills, and services etc are sealed and building works completed.

This is a key process for completion of the property ready for the CML process.


The benefits for this test was to make sure the newly constructed homes meet or exceed Build Regulations.  

They also offer the benefits for the occupants by discovering drafts, air-leaks or lack of insulation. This makes the home more energy efficient thus reducing greenhouse gases and carbon footprint whilst improving indoor air quality.

We provided the necessary certificates for this development within 24 hours of the test and some while we were on site allowing the CML process to conclude quickly and without any delays.