McAlpine’s £500m revamp: 15 years in the making

With a value of £505m, Sir Robert McAlpine’s transformation of Woking is no ordinary town centre facelift.

The main contractor started on site last summer and will oversee the delivery of 437 apartments, a 189-bedroom hotel and 7,000 sq m of new retail space in staged openings through to spring 2021.

The project, which will see the joining together of two retail blocks, came about following a report, commissioned by funder Woking Borough Council and published in 2006. This recommended an overhaul of the town centre to attract corporate headquarters to the town, which benefits from good links to Heathrow, Gatwick and central London.

A meeting a few years later between property firm Moyallen’s boss Peter Robinson and Woking Borough Council chief executive Ray Morgan led to the formation of Woking Town Centre Management Ltd in 2010.

A development plot was earmarked containing parts of the Moyallen-owned Peacocks shopping centre and the local authority’s nearby Wolsey Place mall as well as other buildings.

Victoria Square Woking Ltd was formed in 2012 to act as client body, with a 52 per cent share owned by Moyallen and 24 per cent each by Surrey County Council and Woking Borough Council. Surrey later sold its share to Woking.

Following an extensive period of relocating businesses, market traders and the fire service (see box), the client went to market for a contractor. Sir Robert McAlpine won the design-and-build deal as well as a management contractor role for fit-out elements.

A two-storey retail podium that will provide some 11,600 sq m of floorspace (including existing units) will be topped by a four-storey car park. A 24-floor hotel and two residential towers 30 and 34 storeys high will complete the project.

Playing catch-up

Work on site began with nine months of demolition before main construction could commence in June 2017. It had been more than a decade since the council-commissioned report recommended major works, yet there was less than half that time now for the project to be completed.

“As things became vacant over the first couple of months we started to assemble the site,” says Sir Robert McAlpine project manager Paul Walker. “We had some service diversions to complete before we could take areas on.”

“Rather than doing one pile a day we did nine or 10 using a completely different installation technology”

Paul Walker, Sir Robert McAlpine

Foundations were next, with the team achieving a significant time and cost saving early on. “Foundations are a piled raft design, which was a joint effort between McAlpine Design and Doran [Consulting],” Mr Walker explains. “This meant smaller-diameter piles than originally specified, with a thick concrete slab on top to spread the load and make the piles work harder.”

Operatives installed some 437 piles, ranging in diameter from 600 mm to 900 mm, rather than up to 1.5 m as initially imagined. “This worked out significantly quicker and cheaper,” Mr Walker adds. “Rather than doing one pile a day, we did nine or 10 using a completely different installation technology,” he says, referring to the switch from bentonite bored piles to CFA.

Piling was initially carried out for tower one, the hotel and the retail podium. A second phase took place in January and February this year once a sizeable Boots store on the site had been demolished.

A sheet pile wall was required for the basement of tower one, which will contain the plant for both residential towers, as well as cycle stores and bin stores. Here the challenge was the water table. “In tower one there was water to about 1 m above the base of basement level,” Mr Walker says. “Thames Water’s sewers were at capacity so we couldn’t use those. We used ejector wells and pumped water to another well to effectively recirculate the water so none had to be taken off site.”

Increasingly bigger machines

Excavation required intricate planning at times. “We had sheet piles on two elevations – there is a 3 m difference across the site,” Mr Walker says. “There were logistical challenges with the ground support, as we were using props with diameters in excess of 1 m. Working around them with 30-tonne excavators was difficult.”

The team dug down 1 m, put in the props then set about excavating further. “We used mini-diggers to take soil back to a point where a bigger machine moved it into one zone, before a bigger machine again took it from there. We had to do it in the right order.”

Logistics remained a challenge on the town centre site. “We had a partial road closure of Victoria Way on the edge of the site, but we could not afford to have people parking on it, so we had to bring the wagons to another part of the site and manoeuvre them out again,” Mr Walker says. “Separating vehicle and pedestrian movements is difficult. We have specific lanes and crossing points.”

Managing the movement of people and materials requires particularly strong communication. “Our subcontractors’ supervisors wear black hats, and at the beginning of each day all the black hats give briefings in terms of what will be happening on site,” Mr Walker says. “That comes from a briefing from our works manager at 4pm the previous day for the black hats. Effective communication is important.”

The hotel core was the first to start going up, as it did not require a basement and has to be handed over for fit-out in time for a 2020 opening. A crane for the hotel build has been climbed twice after attachment to the building core.

“The biggest challenge will be moving workers and materials vertically up the buildings. We will have 800 people on site at peak”

Robert Walker, Sir Robert McAlpine

The first climb saw the crane tied back to the built core and extended by 20 m before a further tie allowed for the second extension.

One of the cranes for the residential element will eventually reach a height of 160 m. Another will use a gravity base on top of the retail podium, meaning the structure has to be propped to its original foundations.

At the time of CN’s visit, the hotel and residential tower one are well out of the ground, while the slipform process is under way for the concrete pour for housing tower two. The retail podium, which will be dominated by a 4,600 sq m Marks & Spencer store, is being built across from the hotel end towards tower one, with the car park above going up at the same time.

Work has progressed at pace during the project’s first year, and there have been no reportable safety incidents. But there is no back-slapping just yet – the team is well aware of the difficulties that lie ahead on the scheme.

“The biggest challenge will be moving workers and materials vertically up the buildings,” Mr Walker says. “We will have 800 people on site at peak. As well as the tower cranes we will have hoists and use the lifts, which we will refurbish before handover.

“We are building in an integrated way so when a frame is at level 30, the envelope will be at level 20 and the fit-out at level 10. It will become logistically challenging.”

So long as these management headaches can be overcome, Sir Robert McAlpine will be on course to complete half-a-billion pounds of regeneration by 2021 – 15 years after the plans were first mooted.