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Home Features Mercer Scaffolding showcases complex scaffold at Covent Garden

Nestled in Covent Garden, London, just a short walk from the bustling markets, a large-scale renovation is underway to convert a Victorian office building into a hotel development. Mercer Scaffolding has the contract for this complex city centre project and is working with 48.3 Scaffold Design and Tufcoat. Jenny Gibson reports.

Almost every commercial scaffolding contract comes with a need to balance erecting a structure that provides safe access to operatives with causing as little disruption as possible at street level. And nowhere is this more of a challenge than in central London, where high footfall, busy commercial premises and narrow streets all need to be given due consideration.

Mercer Scaffolding has the scaffolding contract at 31-33 Bedford Street in Covent Garden for this office-to-hotel conversion. Mercer’s operations manager, Adam Millgate, sets the scene. “The building is occupied with restaurant premises on the ground floor, there’s an adjacent building to the right, and access is required to St Paul’s Church to the left, so each side of the building presented a different challenge on-site,” he explained.

“We were given a 12-week programme to have what we describe as a ‘piece of art’ erected and complete, which we adhered to. The front elevation is 30m high, raised ‘double width’ to support huge loads and facilitate the staircase and hoisting requirements. The scaffold also includes a 16m free-standing section from the last tie position. This free-standing section is one of the reasons we brought in the expertise of 48.3 Scaffolding Design,” Mr Millgate added.

Ben Beaumont, managing director at 48.3, outlines the design considerations. He said: “The front of the building, along Bedford Street, faced onto a busy street with high pedestrian footfall. The pavement had vaults below and the businesses in the ground-floor units were to remain fully open and undisturbed for the duration of the project.

“The side was the main access route to St Paul’s, which had events and congregations most days requiring continuous access to be maintained. The rear was the most straightforward with the scaffold based in a lightwell. Having said that, the return down the southern elevation was occupied at ground level with the adjacent property, so this had to be entirely bridged over.”

The scaffold needed to provide a full protection and loading gantry to the front with complete access to the front elevation above, two staircases, a two-tonne lifting beam and an electric winch. It then needed to continue upwards to provide support to the high eave of the temporary roof. Only in seven locations does the scaffold at the front come to the ground, typically taking the form of 0.40m x 0.60m towers strategically positioned on the pavement, with back propping installed below.

At the side of the building is a narrower protection gantry supporting the full-height scaffold, and the rear scaffold is generally ground-based without the need for propping.

One particular challenge to overcome was the installation of a monopitch roof so high above the existing structure. Mr Beaumont continued: “The developer and main contractor wanted to be able to build another storey of the building and fit it out under the weather protection of the roof. To add to the complexity, the last feasible tie location, where fixings capable of supporting the large roof-generated tie loads could be located, was some way down from the top of the building. This meant that the scaffold had to free-stand around 16m from the last tie point, making the stiffness and rigidity of the scaffold critical.

“During construction we made several visits to site and were thoroughly impressed with how well the scaffolding team at Mercer had done erecting the complex scaffold in the challenging city centre environment.

“Getting the 1250mm deep main gantry beams in exactly as drawn was the only time we had to tweak the design to avoid the building, which was slightly different on-site to the survey drawings. Mercer erected this gantry over 20 shifts throughout the night, working under a ‘noise’ licence by Westminster council.”

“The team made thoughtful suggestions when making those updates as they had been active in the design process from the outset. What could have been difficult problems were overcome quickly and easily in a collaborative team effort,” Mr Beaumont summarised.

Mr Millgate added: “Another challenge of this complex scaffold design was the ‘double width’ front elevation. This was cross braced to provide the support needed and 48.3 suggested using the new Klawz fittings. This removed the need to ‘treble check’ every brace, reducing the fittings on this element by 50 per cent.”

Other impressive aspects of this scaffold design and construction include over 400 beams (Dessa, Layher and Ladder) being used to provide safe and workable design which gave the lift heights needed.

It was Tufcoat’s role to providing weather protection and screening at 31-33 Bedford Street. The company’s marketing and brand manager, Barry Kirkham, provided the details. “Tufcoat installed both our traditional shrink-wrap sheeting as well as a PVC mesh to ensure the site was protected from the elements and screened from view using Capco’s classic monochrome branding.

“The scaffold elevations facing Bedford Street and Inigo Place were covered by the PVC mesh, which was installed as a single piece onto a subframe during the evening to reduce disruption to the restaurant. Weighing nearly 700kg, the mesh installation presented the challenges of not only raising it 30m above street level and working around the gantry but also manoeuvring the 50m mesh carefully over the Grade II listed gateway.

“The remaining elevations and roof were encapsulated using 1600m² of black Tufcoat shrink-wrap installed over five days. This element of the project was not without its challenges as with high winds forecast, the 750m² roof was created in just over two days to ensure it was finished before the weather turned,” Mr Kirkham concluded.

ADS Security Installations provided the super flush hoarding, di-bond and security system with CCTV to every lift. Managing director Jay Lamb said: “It was very important to work around the trading hours of the businesses below and sequence the installation for minimal inconvenience.”

Dave Norman was Mercer Scaffolding’s site supervisor for this programme. He said: “It’s been a challenging project, but a pleasure for the team and myself to be given the opportunity to work on such a complex scheme.

“Many long nights and days were given by all involved, and a huge amount of passion and pride has been put into this project. Mercer Scaffolding is fortunate to have clients and partners which equally believe and share the same qualities and ethos.”

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