Plans to compel housebuilders to carry out airtightness tests on new properties could result in significant delays for buyers looking to move into their homes – because of the British weather. <p></p><p>A new BSRIA guide to airtightness testing, which is set to be introduced in an updated Part L next year, reveals that the tests are extremely sensitive to wind speeds. “If the wind speed is higher than (3m/s),” says the guide, “the test will need to be carried out on a calmer day.” </p><p>A wind speed of 3m/s translates to Two on the Beaufort Scale, described as “wind felt on face, leaves rustle”; some areas of the country have average wind speeds in excess of this all year round. Housebuilders fear testing in some regions could become nigh on impossible and are keen to see a robust details approach to testing homes. </p><p>“This could become a postcode lottery for airtightness tests,” said Dave Baker, chief executive of Robust Details Ltd – the body carrying out testing for sound insulation regulations. “But if the new regulations are written in a way that allows RDL to produce an alternative set of solutions, we could compile an accurate national database and bring …