Competition between retail chains has never been more intense. In the aftermath of Asda's takeover by US giant Wal-Mart, British chains are racing to open stores as quickly and cheaply as possible. In a bid to steal a march on its rivals, Tesco has followed the lead of fast-food giant McDonald's and hotel groups such as Hilton International and Forte by piloting modular construction at one of its stores.
One of the main attractions of modular construction is the time it saves. Using traditional methods, construction of a Tesco store usually takes about 28 weeks. Using a modular system, the store in Haslemere, near Guildford, was completed in 22 weeks – and within 16 weeks of the modular panels being delivered to site. "This gave Tesco an extra six weeks' trading time," says Roger Kier, associate director of project manager Schal.
However, the time-saving potential of prefabrication was not fully realised at Haslemere, says Keith Jones, operations manager at prefabricated building manufacturer Yorkon, which supplied the Tesco system. "A completion time of 12 weeks on site should be easily achievable," he says. He attributes the four extra weeks to planning problems: "Planning permission was granted long before Yorkon was involved in the project, and permission was based on a traditionally built Tesco store." This meant that Yorkon's modular system had to be adapted to the traditional design.
The biggest hurdle for Schal was that the planning authority wanted a pitched roof. Haslemere is a quiet market town and the store was to be constructed in a prominent town-centre location, on the site of a now-demolished leisure centre. The planners insisted on a traditional look and, in particular, on a pitched and clay-tiled roof.
Weathertight in three weeks
Work started in Haslemere on 4 January 1999 with the construction of the ground-floor slab. At the Yorkon factory in York, assembly of the cladding modules began. On 15 February, the first modular wall and ceiling panels arrived. Less than three weeks later, the 2600 m2 store was fully clad and weathertight and the subcontractors were able to start work on the interior.
The walls and ceiling were built using Yorkon's modular free-standing Hi-Bay units, which enable wall and ceiling cladding panels to be craned into position from a lorry. The team put up one 12 × 3 m roof panel every 15 minutes. Erection of the wall and ceiling panels started at one side of the central atrium and progressed around the perimeter to finish back at the atrium. Jones was keen to emphasise that 3 m panels were used only because they matched pre-ordained planning specifications, and that 4.2 m panels could have been used instead, reducing construction time further.
Yorkon has not yet developed a modular system for an atrium, so it was constructed using traditional methods while the store fit-out was under way.
Roofing and services subcontractors also benefit from the modular method as they do not have to wait for the fit-out of the store to be completed before starting on the roof. Roofers can stand on the ceiling without using scaffolding because the walls and ceiling are constructed as a watertight free-standing unit. Once the roofers had finished, the mechanical and electrical subcontractors moved in, using the ceiling as a platform for installing ductwork and trunking in the gap between the ceiling and the pitched roof.
Most of the store's exterior was clad using the Hi-Bay modular system, but the office areas were created from Yorkon's volumetric system and delivered to site 90% complete, with electrical wiring, fixtures and finishes in place. Jones says: "The reason offices were not 100% complete on delivery is that Tesco was insistent that the layout and size of the office space were exactly the same as their 'standard store' model." Unfortunately, this did not correspond with the office modules, so some rooms were constructed from two or more modules, which meant there was finishing work to be done on site. Tesco also insisted that the IT cabling be installed without connectors between the rooms, unlike the electric cabling. This meant that IT installation had to take place after office installation was complete.
"With a few simple changes to the office layout to complement the module's dimensions, the whole office area could have been completed in much less time," says Jones. Tesco is said to be reappraising the use of connectors in IT cabling, so that the cables could be installed at Yorkon's factory with all the electrics.
The Haslemere store, which cost £5.3m, was opened at the end of July. Tesco has declined to say how much, if any, money was saved using the modular system. However, Schal's Kier says: "There was no cost advantage in this instance; the store was a prototype." He insists that if modular construction had been planned for the store from the outset, Tesco could have expected cost savings. But Kier is keen to emphasise the system's advantages: it enables stores to be built more quickly and opened sooner; the construction timetable is not dependent on weather, which is important during the winter; and retailers do not have to wait for finishing trades to tidy up loose ends, as panels are delivered fully furnished.
For Tesco, the store might have been a revolution in construction, but for the customers, it is probably just another Tesco – albeit one that opened a few weeks earlier than they might have expected.