Home Builders Federation seeks time to develop simplified method for meeting air-tightness requirements

The government will decide in the next fortnight whether to delay some of its planned revisions to energy-efficiency regulations for a year so that housebuilders can develop a simplified system of compliance.

In its draft consultation on Part L of the Building Regulations, the government stated that sample pressure tests should be carried out on all housing developments to prove that homes had been built to meet air-tightness standards.

But the Home Builders Federation is lobbying for the introduction of a system of robust construction details designed to eliminate the need for pre-completion testing. The advantage for housebuilders would be meeting the requirements of Part L without having to carry out expensive pressure tests.

If the government gives the proposal the go-ahead, the HBF will need 18 months to develop a pattern book of robust details. This means that the air-tightness requirements of Part L, which are due to come into force on 1 January 2006, could be delayed until January 2007. Dave Mitchell, HBF technical director, confirmed: “We are pressing the government for a delay.”

However, environmentalists have expressed concern that the proposal will allow housebuilders to build to a lower standard. David Strong, managing director of BRE Environment, said: “Many builders regard robust details as a get-out-of-jail card. There is no substitute for the benefits that would accrue from pressure testing.”

Many builders regard robust details as a get-out-of-jail card

David Strong, BRE Environment

Strong added: “Pressure testing is the next big win. The insulation levels being proposed for the Part L revision could provide diminishing returns if we don’t achieve a reasonable standard of air-tightness.”

Robust details for Part L would work in a similar way to those already implemented for Part E, the regulation governing acoustic performance in dwellings. These were introduced in July 2004 by testing company Robust Details Ltd, after the HBF had lobbied government for an alternative method of compliance. The decision led to the robust detail method of compliance being introduced six months after the rest of Part E.

As well as the cost of pressure testing, housebuilders are afraid of the consequences of failing the tests. Mitchell said: “There will be a delay while the fault is rectified, then you will have to get the tester back. It will add costs, slow down the industry and the rate of building.”

Pressure testing will be mandatory for most non-dwellings from 1 January 2006.