Literally. Doncaster's Earth Centre is made of used radiators, old cement and reclaimed timber – and it's the cutting edge of design.
Guy Jackson is clearly proud of an amorphous collection of old cast-iron radiators stacked neatly outside his site hut. "We've had to scour demolition sites and salvage yards all over Doncaster to get these," he says.

The pile of recycled radiators is the first clue that things are a little different on this site.

The radiators will be used to heat the new low-energy conference centre and entrance buildings currently under construction at the Earth Centre, where Jackson is project manager for contractor Taylor Woodrow.

Jackson stands outside his site hut, boots sunk in the mud, shoulders hunched against the bitter wind that whips off the Pennines, contemplating his hard-fought acquisitions. Then he's off. Marching across the site, keen to show the work his team are doing at the centre and to explain how the contractor has adapted to working on a millennium project billed to "inspire understanding of sustainable development".

Striding out of the hut compound, Jackson warms to his task. "You see this," he says, shouting to make himself heard against the wind, sweeping his arm in a broad circle to highlight an expanse of newly landscaped ground. "This was originally an old slag heap, from the days when this site was a colliery."

He explains how, earlier last year, the area was landscaped to sculpt an amphitheatre for outdoor performances in the summer. "To get the grass to grow on the colliery waste, we had to mix treated sewage into the top 700 mm to get some organic matter into the ground. By spring, this will all be covered in vegetation."

Then he's on the move again, pacing purposefully along a muddy, rutted path towards the new entrance building. "See that lake," he says, without breaking pace. "We built that to hold the rainwater run-off from the landscaping around the amphitheatre. It stops the rainwater from flowing straight into the river, to reduce the risk of flooding."

As project manager for Taywood, Jackson is responsible for the design-and-build contract of the second phase of works at the Earth Centre.

In its nine months on site, the contractor has completed the landscaping of the amphitheatre and construction of a new electricity substation. The firm is also responsible for the construction of the ill-fated entrance canopy, where a delivery of steel of a different grade to that specified has temporarily halted work. Their endeavours are now directed at completing the stunning new entrance building and conference centre, both designed by Bill Dunster Architects, ready for an Easter opening.

Now almost complete, the entrance building stands on a series of wooden legs, high on the riverbank overlooking the Don, its gently curving wooden roof echoing the surface of the river below. The building has been constructed from a host of recycled materials, most of which have been sourced locally. Jackson stops outside the door to introduce section manager Matt Armitage, the man whose task it was to source the materials. "Matt found the wooden pylons that support the building in a local lorry park," says Jackson.

Like Jackson, Armitage talks knowledgeably and enthusiastically about sustainability and sourcing materials with low embodied energy. He is clearly pleased with his contribution to the project and, in particular, his pylon discovery. "They were a bit of a bargain," he says. "The architect had specified turned Douglas fir for the columns – it would have set us back about £20 000 to buy them new. We paid just £15 a pole for these," he says, proudly. "And one of them had 'GPO 1909' written on it!"

However, having acquired the poles, the next task was to finish them to an acceptable standard for use in the building. Nobody was prepared to risk their lathes on recycled timber. "In the end, we had to build our own lathe," explains Armitage. "It was a real Bodgit & Scarper operation – but it worked."

The building is constructed mainly from timber. The wooden legs support a glulam frame that had to be sourced from France. "It was the only place we could find a manufacturer that could produce the glulam with the tight curves needed for the roof," explains Jackson. The manufacturer's concern over quality meant that only new wood was used to form the beams. However, most of the building's remaining timber was either recycled or came from Forestry Stewardship Council-certified sources.

To ensure a sufficient supply of timber, Jackson and his team have built up a local network of contacts and suppliers. "We know all the local scrap merchants and yards," says Armitage.

"And they know other suppliers, who have friends who know someone else." The contractor was fortunate, too, in that an ex-miner had set up a salvage yard nearby specialising in reclaimed timber. Other hard-to-find materials were obtained over the internet, through recycling organisations such as, where a finder's fee is charged for locating each item.

Even with this extensive network of local suppliers, it was still proving difficult to furnish the contractor's needs. "We got to the stage where Matt was finding out which local buildings were due to be knocked down, and then talking to the preferred demolition contractors while they were still looking at the site," says Jackson. "At one point, things got so bad that Matt had to set off with £100 of petty cash in his pocket to reserve some radiators that were desperately needed for the entrance building," he says, grinning.

Having committed the team to the use of recycled materials, Jackson's next problem was finding a subcontractor prepared to work with them. "At first, we couldn't find any subbies willing to work with recycled timber," he says.

The carpenters were concerned about varying levels of moisture in the timber and expensive tools getting ruined on old nails. The problem was only overcome by Taywood taking on the risk of sourcing materials and underwriting any problems the subcontractors might have.

To its credit, Taywood has also pioneered the use of new forms of recycled materials. Powdered ground granulated blast furnace slag (GGBS) – usually a waste product dumped and buried as landfill – was used to replace up to 70% of the cement in the building's concrete ground beams. "Cement has a tremendous amount of embodied energy," explains Jackson, "so replacing it with a waste product is better for the environment."

Alistair Hunter, Taylor Woodrow's design co-ordinator and engineer-in-charge, is more specific: "Normal reinforced concrete has 325 kg/m3 of cement; concrete made using GGBS has only 100 kg/m3." The main drawback with this cement is its slow curing time, which could extend the construction programme. "It takes 56 days to reach its design strength, as opposed to 28 days for normal concrete, so it would be difficult to use for multistorey constructions," explains Hunter.

Initial attempts to use the new material were not without their problems. The team reduced the water content to increase the strength of the concrete, and then added plasticiser to make it more workable. Unfortunately, too much plasticiser was used, which made the mix difficult to work with.

"It was a bit embarrassing," says Jackson.

With rain clouds starting to loom on the horizon, Jackson is keen to finish his tour. Next stop is a small electricity substation that looks like a terrace of three domestic garages. "It's a bog-standard substation constructed from normal blockwork that can be demolished and crushed at the end of its life. We've used recycled joists to support the roof and topped the roof with sedum [a kind of succulent] to slow rainwater run-off," says Jackson, adding that the building was constructed at no extra cost. "The client thinks this is his most sustainable building."

The tour takes in the site's recycling compound. Here, waste wood, stone, hardcore, metal, plastics and insulation all have their own bins. "All the materials are separated on site before they're sent to a recycling centre down the road – which reduced costs slightly – with the exception of plastic for which there are no recycling facilities," explains Jackson. "It's taken a bit of cajoling to get some of the subbies to separate their waste materials, but they have eventually taken it on board."

Stopping on the hillside overlooking the conference centre, Jackson points to a team hard at work placing lumps of concrete by hand into gabion cages that line the building's circular walls. "The crushed concrete is from an old colliery four miles down the road. And the guys putting the concrete in the cages are all local lads – so we're contributing to both social and economic sustainability, too," says Jackson, sounding more like a local politician than a project manager. The finished effect gives the conference centre the appearance of being constructed from a series of interlocking dry-stone walls.

The conference centre will be the centrepiece of the site. It features a large, circular main auditorium surrounded by three smaller, satellite meeting rooms. Once again, Jackson is keen to demonstrate his knowledge of the building's environmental strategy: "The massive walls act as a heat store, helping the building stay cool in summer and warm in winter."

As with the the entrance building, recycled materials are a major feature of the conference centre's construction. The steelwork I-beams for the roof came from a demolition site, and the steps leading into the centre will be made from recycled railway sleepers. These will be easy to source – "They're big on railway yards around here," says Jackson. The roof covering was another area where Taywood's salvage scavengers were involved. "We've looked at using the sides of lorries, even at old motorway signs, but we found that a lot of these materials are already recycled," says Jackson. In the end, a sedum roof was selected.

Jackson's knowledge and enthusiasm for sustainable construction is impressive, but it is tempered with a note of realism. "We have had to balance the environmental benefits with costs and a tight construction timetable," he says, splashing through the mud on the way back to his site hut. "The client gave us a sustainability brief. We've used it in certain key tenders, but not others, because you have to bring people with you rather than dictate to them."

One of the biggest problems for anybody using recycled materials is guaranteeing the work. "It is an issue with recycled materials – particularly on a design-and-build scheme with a guaranteed maximum price," says Jackson.

Back in his site hut, the recycling theme is continued. "This project has illustrated to us that recycled materials are viable for some applications," says Jackson. Taywood Homes, for example, is now looking at the possibility of using it for some applications. "If there is one thing we've learned on this project, it is a sense that these things can be made to work," he says.

Guy Jackson:
Taywood project manager

Jackson has worked for Taylor Woodrow since the late 1980s. His early years were spent working for the company’s facilities management arm before he moved into construction. Before his stint at the Earth Centre, he was based in Hong Kong for three years as the client’s project manager on the Festival Walk scheme. “It was fantastic,” he says. Jackson says his involvement in the Earth Centre project comes from his interest in sustainable issues – that and the fact that he prepared the bid. Jackson will give a presentation of his experience using sustainable materials at one of Taywood’s sustainable network meetings. Project managers on other projects will then be able to make a decision on the use of reclaimed materials on other schemes within the group.

How a project team can promote the use of recycled materials

  • Encourage the use of recycled materials in the scheme’s design
  • Demonstrate new practices in trial projects
  • Increase the use of reclaimed and recycled materials by changing design practices
  • Ensure the design does not constrain the use of recycled or reclaimed materials
  • Maximise reclamation and recycling opportunities after demolition at the end of the project’s lifetime
    Quantity surveyor
  • Consider the location of the site and the application of the material in the decision to use reclaimed materials
  • Consider the use of recycled materials to minimise environmental or amenity impacts; for example, where their use would reduce traffic movement
  • Increase the use of reclaimed/recycled materials by maximising the opportunity for their use in specifications, and by proposing alternatives where the design and specification may not allow them
    Materials suppliers
  • Provide recycled materials of a guaranteed quality and quantity to give contractors the confidence to use them
    Taken from the Construction Industry Research and Information Association publication, The Reclaimed and Recycled Construction Materials Handbook. Available from the CIRIA, tel 020-7222 8891, £40 members, £80 non-members.
  • The conference centre’s environmental strategy

    The Earth Centre’s conference building is a super-insulated box, partly buried in the ground. This means its heat loss is a fraction of what would usually be expected for this kind of building. It has a natural ventilation system, driven by the wind, with a heat exchanger to transfer any heat from the outgoing air to the incoming air. The combination of these two systems means the heat load for the building is very small. Solar collectors mounted on the building’s roof heat water. This is circulated through a 400 m3 insulated water tank buried beneath the floor of the building. The solar collectors will heat this tank throughout the summer. In winter, the heated, stored water will be circulated through radiators to heat the space. If the heat stored in the water tank runs out before the end of winter, a wood-fired stove will provide the necessary top-up heat. A wind generator mounted on the boiler flue will provide part of the building’s electric power needs.

    Green gauge

    More industry views on the future of sustainable construction
    We’re finding that clients and architects are requiring that BREEAM, which gives scores of “good”, “very good” and “excellent”, assesses their work. Increasingly, clients are saying that they want a BREEAM “excellent” building.
    Bill Addis, co-ordinating environmentally responsible construction at Buro Happold First, we are addressing energy by improving thermal efficiency. Second, we are reducing wastage in the build process. Third, we have done on-site recycling with grey water and are looking at rainwater harvesting. Finally, we have established so we can be certain about the sourcing.
    John Weir, group design and marketing director, Wilcon Homes It’s important to point out that energy is a moral issue. Energy costs are rarely more than a quarter of costs and the amount of effort that has to go into minimising those costs is not justified in terms of economics. The effect on the environment is the issue.
    Bernard Williams, QS, facilities management consultant Bernard Williams Associates Houses need south-facing roofs at about a 20° pitch so photovoltaic panels can be more cost-effective. The fabric itself will be super-insulated, it will have a 5 m solar water-heating roof panel to heat 50% of the water. More attention will be paid to reducing electricity consumption and more efficient white goods will be produced.
    David Turrent, director, ECD Architects