Buildings failing airtightness

BRE has reported that around a third of buildings tested are failing airtightness tests. The claim comes two and half years after the introduction of Approved Document L2.

Mike Jaggs, head of BRE’s airtightness service says: “A large number of companies still seem to be unaware that Building Control has to be satisfied that a building is airtight before it can be signed off. This means that designers and contractors are not addressing the issue at the start of a project when it is very often quite simple to put in place the right design and workmanship principles.”

Failure to pass the test can mean that the work on the final stages of a project has to be re-done, adding to the time and money spent on a job. “It comes as quite a shock to clients when they suddenly realise they haven’t designed or built for airtightness,” says Jaggs.

David Pickavance, manager of airtightness testing at BSRIA and chairman of the Air Tightness Testing and Measurement Association agrees with the proportion of buildings failing: “It is a high number to be failing because the Building Regulations level is not difficult to achieve. Airtightness is not given the importance in the construction quality assurance process that it should be.”

Pickavance suggests that failure in some cases could be due to the complexity of projects, but Jaggs argues that the nature of the building should not come into the equation.

“It’s a matter of attention to detail; everyone needs to know what has to be done and why. Success doesn’t depend on building type – complex buildings can pass and simple buildings can fail,” says Jaggs.

Pickavance added that the use of an expert on airtightness during the construction process would see more buildings passing: “Expert knowledge is very valuable because you would cut out the failure and the cost of remedial fixing and lateness.”

BRE says that some building control bodies are applying the air permeability requirements more strictly than others.