The A team

Since the partnership was announced in June 1999 Beazer has opened the new Torwood2 timber frame factory in Ipswich and built a prototype timber frame house at the Gas Research and Technology Centre in Loughborough. Lessons learnt from these ventures are now being fed into the construction process at Deptford.

The development of the first Amphion project is, according to Hyde Housing Association chief executive Charlie Adams, "a seminal moment in housebuilding". He believes that the timber frame system will substantially reduce costs - and provide a basis for implementing future innovations. "Water recycling, solar energy and home automation can be introduced once a basic idea has been established," he says.

Hyde is one of three founder members of Amphion, and the Childers Street site in Deptford is one of four Amphion sites it has in the pipeline. The Childers Street scheme is the last of eight sites to be redeveloped on the Evelyn Estate in Deptford. It provides a test of the versatility of the Tee-U-Tec timber frame technology as it comprises 19 three-bed houses, two four-bed houses and six one-bed apartments.

Design is by PRP Architects. "We were able to think about timber frame housing in a thorough way because it is being factory produced in a controlled environment. We have spoken to a range of housing associations about timber and steel and there's not much resistance," says managing director Barry Munday.

As well as manufacturing the timber components Beazer has design and build contracts for Amphion developments such as Hyde's Deptford site. Its erection team is now developing the skills it learned in building the Loughborough prototype.

"At the moment it takes six hours to felt in a one-off house," says John Low, chief executive of the Beazer Group. "With practice that time should fall to five hours for a detached house. The objective is to reduce by 50% the time it takes to build a house."

A team of seven is responsible for the unloading and fitting the system of timber panels, roof trusses and floor cassettes (see box). Their activity is closely co-ordinated with the arrival and operation of the supply lorries and crane.

"Traffic management is fundamental, especially in a confined space such as Deptford," says Low. The erection team has to look at the optimum positions for the crane and lorries so that components can be easily lifted into position.

Components take approximately one and a half hours to unload from the trailer. At the moment the project team has to co-ordinate the arrival of lorries from both Torwood factories. Torwood1 supplies the floor cassettes and roof trusses, while Torwood2 manufactures the panels. By the end of the year Ipswich will provide every component for Amphion, which means that the efficiency of the construction process won't be dependent on lorries arriving on-site at the same time.

Deliveries are arranged so that most of the hired drivers' time is spent on the road. Once a trailer has been unloaded it is driven back to the factory where the drivers's cab is hitched onto another fully laden trailer before being driven back to the site.

Apart from the roof trusses, which are assembled on site, components are unloaded from the trailer directly into position. While a crane handler attaches panels to the crane, two erectors guide panels into place with the aid of a guide rope. The panel is then temporarily nailed into place before being permanently bolted in by another erector.

Unloading cassettes and timber panels efficiently is crucial to reduce overall build time. Closed floor cassettes are lifted using joists as craning points. These are accessed through four circular holes created in the factory, which are subsequently covered by roundels. The exposed joists can also be used for service access and to secure workers' harnesses to the superstructure.

At the moment insulation between joints takes place on site but Beazer is looking to produce airtight components at Torwood. In the autumn Torwood2 will be fully automated, which means that factory-built panels will include windows, services, insulation and plasterboard. Beazer is also gearing up for modular production. "In January we aim to be producing completed units. Main and en suite bathrooms, cloakrooms, and kitchens will all be pods," says Low.

Beazer expects to make savings by rationalising its supply chain. "In time we will be able to get all our supplies sent to our factories. It means we will be able to practice just-in-time systems of delivery. Already in Scotland we only have half-a-day's worth of timber in the factory at any one time," says Low.

The homes at Deptford are clad mostly in brick because planning permission was won before Hyde decided to build using timber. Low expects the proportion of brick to cladding systems to fall in future developments as the Torwood production lines explore factory cladding options.

Beazer is so keen to maximise off-site build that it is even considering pre-attaching scaffolding to timber panels in the factory.

Beazer's level of interest in timber frame technology isn't surprising. As the exclusive Amphion supplier it has a guaranteed market, making its investment virtually risk free. What's more Beazer can apply the process to the private sector either as a housebuilder or a supplier. And Low says the figures are already adding up.

"Production costs are 10% higher at the moment but the savings made on site make up for the extra cost. We reckon that those using brick and block will have to spend 10% more anyway on construction costs to reach the U value standards required by Part L."