Brand new tradition

This is certainly the case at the New Haberdashers' Hall on the edge of the Square Mile in London. Here is a site where the project manager drinks his tea from a monogrammed mug. And forget wipe-clean plywood – the meetings here are held at a polished boardroom table so large that it almost fills the site hut. Even Jim Dunn, the contractor's project director, is turned out in a smart shirt and tie.

Dunn, the man responsible for construction of the £7.7m hall, looks more like a bank manager than a construction boss - only his spirit-level cufflinks, crisply reflected in the table's gleaming veneer, give away his profession.

It is a profession he is passionate about. "To get quality, you have to give something extra to the project," he enthuses. He can hardly wait to show off just what this very traditional contractor has brought to the project. He dashes into his site-hut office, perched on a plot of land borrowed from nearby Smithfield Market, to grab his hard hat. A glimpse through the open door reveals a large, tidy, polished wooden desk with a black leather and chrome swivel chair. In the corner of the office, propped against his filing cabinet, is a tightly-furled golfing umbrella covered with HWA monograms, reinforcing the impression that, perhaps, Dunn is really a bank manager after all.

Any such thoughts are dismissed, however, on his reappearance. Resplendent in a gleaming white hard hat (with HWA monogram, naturally) and high-visibility jacket, he sets off towards the building, which is now almost complete.

As he strides purposefully ahead, weaving between the piles of materials stored ready for use, he explains the difficulty that the somewhat compact site has presented the construction team: "There are six party-wall agreements, all with business premises that encircle the site." But despite having so many interested neighbours, the contractor has managed to go about its work so discreetly that it has twice been granted the Special Award under the City of London's "Considerate Contractor" scheme.

The New Haberdashers' Hall is squeezed among a haphazard jumble of mundane six- and seven-storey office and apartment blocks. The more modestly proportioned, two-storey hall has been constructed around a formal rectangular courtyard. It has a pitched lead roof, handmade-brick walls and a cloistered ground-floor corridor.

Compared to the surrounding office blocks, the hall seems very traditional and sedate in its design – even retrospective. Dunn pooh-poohs such a suggestion. "The building is not a retrospective design," he insists, "but a modern design using traditional materials to reflect the livery company's 500-year history."

It is a similar brief, one imagines, to that which Hopkins had for Portcullis House, the new parliamentary building in Westminster. In fact, prior to starting work on the scheme, Dunn was taken round Portcullis House by Amir Sanei, the project architect from Hopkins and Partners.

Standing in centre of the courtyard and surveying the scene before him, Dunn says: "We had to draw on traditional trade skills for this project." Looking upward, the most obvious traditional feature is the building's pitched lead roof. "The roof is very special," Dunn says proudly. It is clad in more than 700 lead tiles, each weighing more than 100 kg. The tiles are diamond-shaped, measuring more than 1 m across and 1.5 m in height. "We probably had all the most skilled lead workers in the south of England working on this project," Dunn boasts.

The cladding of the roof has evidently been quite a challenge. Each lead tile has been laboriously hand-assembled in a small workshop on site, by specialist T&P Lead Roofing. Although the materials are traditional, the roof's construction is unique. So, before work could start on site, the contractor had to build a mock-up of a section of the roof at its works in Stanford-le-Hope, Essex.

Each tile is fabricated around a diamond-shaped piece of marine plywood, Dunn explains. Lead is rolled over the wood's top surface and attached to its underside using copper nails. Finally, an additional lead flashing is welded to the top two edges of the lead-covered diamond. Once installed, the flashing will slot underneath the tile above to keep the roof watertight.

Dunn is keen to show the lead workers' skills in action, but their workshop is empty. The only clue to its use is the rolls of lead piled in one corner, a plywood template placed on a trestle, and a welding torch lying idle on a bench. It seems the entire team is up on the roof, fitting the tiles. "I've given them a bit of a hard time recently," Dunn admits, "just to ensure they keep to the programme."

But there is more to admire from the vantage point in the courtyard than just the building's roof. Its dark grey patina creates a striking contrast with the rich red of the brickwork walls surrounding the open space. A series of arched cloisters line the courtyard on the ground floor, solid brick piers forming an open colonnade. On the first floor, these are mirrored by large sash windows.

Like the roof, the 13-inch thick walls deserve an explanation from Dunn. "The walls are solid and constructed from handmade bricks bonded with semi-hydraulic lime mortar," he says. "It's probably one of the biggest cement-free projects in the UK." In all there are more than 400,000 bricks on the project.

Dunn speculates that there were three reasons for the architect choosing lime in preference to a Portland cement-based mortar: the fact that large expanses of brickwork do not need expansion joints, the superior colour and appearance of lime mortar, and, he suspects, "the romance of using a material that has been around for over 2000 years".

The use of such a traditional construction method has not been without its problems. The time taken for the mortar to gain sufficient early-day strength was one problem that needed careful construction programming to ensure the brickwork was not loaded too early. Richard Matthews of Arup, structural engineer on the project, admits: "We got our fingers burned."

The lime mortar took 90 days to reach its final strength rather than the 28 days associated with cement mortar. At 28 days it had achieved less than 50% of its final strength, Matthews recalls.

Getting the mix right is crucial to the strength of lime mortar. Sand has to be carefully selected for colour, gauged for maximum workability and the amount of water used in the mix is critical. The secret is not to use too much water and staff expertise is vital. "It's down to the experience of the man who runs the mixer," explains Dunn. On hot days during this project, to keep the mortar at strength, the bricks had to be pre-soaked in a tub of water to minimise their absorption of water from the mortar.

Finding contractors capable of working with such traditional materials was not easy. "You have to seek out these guys," says Dunn. "We know that to get quality work you have to give something extra, and we try to work with subbies who follow that mentality," he adds. Before he makes a decision whether to work with a particular specialist he visits them in their works. "You can tell a lot about a subbie by the state of their workshops," he says.

All specialists on the Haberdashers' Hall project have been appointed on a competitive tender basis. To ensure he gets the quality he demands, Dunn insists the specialist contractors have a high level of supervision. "Every trade must have its own dedicated foreman," he says.

As he goes inside the building, Dunn greets the tradesmen he encounters by name and enquires earnestly about the progress of their work. Like the exterior, traditional materials are very much in evidence inside. York stone has been used for the flagging on the ground floor where the company's offices and facilities for catering staff are located, and the walls are finished in fair-faced brick or plaster.

In contrast to the natural materials on the walls and floors, however, the ceilings on the ground floor are formed from precast concrete panels. These panels have been acid etched to give a stone-like appearance, creating an impeccably crisp, white finish.

All the main function rooms are upstairs, reached by a 5 m diameter precast concrete spiral staircase. At the top of the stairs is the main reception gallery, connecting the building's function rooms and the main Livery Hall.

Getting to the hall calls for some nifty footwork to step over bundles of cables and service pipework. These services will eventually be concealed beneath oak flooring, but for the moment the final sections of cable are still being laid. Squeezing the services into the building has been a real challenge. There is no service void in the roof, and there are no ceiling or floor voids on the ground floor. Much to Dunn's frustration, all the services have had to be routed through the void beneath the first floor and either fed down to fittings and sockets in the precast ceiling units, or fed upwards behind the panelled oak walls of the function rooms.

One of the most spectacular of the function rooms is the Court Room. This U-shaped room features a series of narrow horizontal windows set into a curved external wall and a cast insitu concrete ceiling slab supporting a narrow clerestory window. The two sets of windows fill the room with a subtle natural light that appears to illuminate every surface evenly. This makes the plasterers' task of creating shadow gaps in the walls a particular headache. They have been spared this in the main livery hall, where wooden panelling will line the walls in place of the plaster.

The Livery Hall itself is a magnificent space, particularly for oak lovers. The room has a high vaulted oak ceiling, the walls are panelled in the same wood and even the floor will have oak boards once the services installation is compete.

"Everything in the hall is important, and all the work is on show, so the detailing needs to be thought through very carefully," explains Dunn, adding with a smile: "You cannot overstress the number of meetings required to thrash out the details to make it all work."

Building the interior of the roof, like the outside, gave the team some of their biggest headaches. The use of traditional materials was a particular challenge because of the large internal space.

Structural engineer Richard Matthews says the roof posed a number of challenges, the main one being the need to design the large number of timber connections to be visually acceptable, as far as the architect is concerned.

It was Gordon Cowley, of Cowley Timber, who came up with the solution. The architect had conceived the roof as a modular construction with hundreds of 2.4 m long glu-laminated timber beams connected at stainless steel nodes. However, to make this solution work, Cowley had to develop and test a new type of epoxy resin that could be injected into the connections, in order to glue the stainless steel to the timber. "This is a pretty radical roof," Cowley says. Dunn agrees, confiding: "It's been a labour of love."

The hall is now nearing completion, and the project is due to be handed over in February 2002. Work started on 24 January so, as Dunn puts it, "this is a real millennium project", despite the traditional methods that have been used.

In the meantime, Dunn suggests returning to his site hut to put those monogrammed mugs to good use.