Full colour cancer care

The £160 million Cancer Centre at Guy’s and St Thomas’ embodies two important, but seemingly conflicting motivations. On the one hand, the client, Guy’s and St Thomas’ NHS Foundation Trust asked for ‘a hospital that doesn’t feel like a hospital’, a non-institutional building with a home-like environment and a human scale.

On the other, the tight programme and restricted site close to London Bridge Station, dictated a heavy reliance on offsite prefabrication, normally associated with uniformity, repetition and a limited palette of materials. 

The solution devised by the design and build team, led by Rogers, Stirk Harbour + Partners (RSHP) and main contractor Laing O’Rourke, was to develop a varied offsite system comprising a range of materials, geometries and structural treatments designed to inject variety and warmth into the architecture. Over 60% of the building was constructed in a factory.

The system includes a hybrid unitised curtain wall with an exterior aluminium frame, brightly coloured panels and horizontal louvres, and an internal glulam frame designed to make patient bedrooms and consulting spaces more welcoming. Main facades feature two vertical exposed concrete shear walls with punched circular window holes, produced by Laing O’Rourke at its Explore factory in Derbyshire, as part of the wider precast strategy for the scheme. Meanwhile, bulging red and blue ductwork on modular panels snakes across the rear elevation in a playful nod to the external services on the Pompidou Centre in Paris. 

Steve Martin, associate partner and project architect at RSHP says: ‘At Guy’s we have really pushed the limits of prefabrication. The range of facade concrete, unitised elements, projecting balconies and external ductwork mean it doesn’t resemble your ordinary offsite system and avoids all notions of institutionalisation and “patient processing”.’

The 14-storey tower stands on the triangular corner of the Guy’s hospital site and brings together facilities previously provided in eight different buildings on two sites. 

It is divided into four stacked care ‘villages’, for welcome, radiotherapy, outpatients and chemotherapy, each with its own ground floor reception area and arranged to break down the scale of the building and simplify orientation. 

Organisation of the internal functions is also split, in plan, between the more clinical and technological treatment areas, at the north end of the site, and the more social parts at the south. The top four floors are an entirely separate unit leased to a private healthcare provider to help finance the scheme.

Contextually, the Cancer Centre stands at the centre of a trajectory of decreasing architectural scale, ranging from the 300m height of the Shard and Guy’s tower to the north, to lower rise buildings to the south.

Martin comments: ‘The detail of the facade doesn’t really relate to nearby buildings, instead we tried to relate to the context using scale and massing. The first balcony level corresponds roughly to the top of buildings across the street. The inclusion of balconies every two or three storeys introduces granularity and breaks down the overall scale.’

The focus on prefabrication was largely a res­ponse to the tightness of the site, on the corner of Great Maze Pond and Snowsfields, which the building almost entirely fills, leaving little space for materials storage or on site assembly. Building in a factory helped reduce the construction programme, and improve quality and safety. However, it also required detailed upfront design coordination, between architecture, structure and M&E. 

Leonardo Pelleriti, former associate and facade specialist at RSHP, says: ‘This was one of our first full-blown building information modelling projects, with clash detection and a federated model, used by the various contractors involved to cut their teeth in BIM. Everything had to be just right when it arrived on site.’

Laing O’Rourke transitioned over 3,000 insitu elements of the original design for the concrete frame into the factory, including 80 per cent of the blockwork walls used for the basement. Its Design for Manufacture and Assembly (DfMA) approach was used to develop the exposed concrete shear walls on the south and west elevations, each of which comprise five precast ‘sandwich panels’ formed of a 90mm outer layer of architectural concrete, roughly 200mm of insulation, and an inner layer of structural concrete. 

Richard Rogers was first to pioneer the idea of turning construction inside-out and exposing the skeleton infrastructure on the outside. At Guy’s, pressure to maximise floor-to-floor heights and limit the verticality of the building informed the decision to run ventilation ducts across the windowless north facade.

The red and blue ducts are fixed to 8.9m-wide prefab panels and vary in diameter from 450mm to 1,100mm. Walkways are attached to panels for access and maintenance and as support. The building’s internal space was further maximised by constructing a 100% modularised 12-storey steel plant tower at the north east corner of the building. The tower was constructed in under eight weeks and incorporates five, 4.2m-high sections, each with an air handling unit to service the corresponding floor.

Excluding concrete elements, the entire facade package was delivered by Structal UK, including the unitised curtain walls, external services and balcony sections. The contractor was one of the few able to fabricate the hybrid glulam timber/aluminium panels on the southern elevations – 840 in total – considered crucial to creating a comforting place for staff, patients and their families.

Pelleriti comments: ‘The larch glulam is more homely than aluminium. It compliments a series of birch ply and bamboo staircases in the care village atria. Structal UK was very good at responding to our aspirations, it was involved from the start of detailed design and throughout construction developing prototypes.’

Double glazed hybrid panels include coloured sections that correspond to the level of the care village behind. Inward-opening, full height, timber ventilation doors, set behind external louvres in the units, form part of a natural ventilation strategy for the southern portion of the building. The louvres work in combination with the projecting balconies and a steel canopy, at roof level, to increase solar shading.

The prefabricated balconies provide outside space and fresh air for patients and staff, but posed a technical challenge for the designers. The large steel modules had to be hoisted and installed over the top of the completed curtain wall without endangering operatives or pedestrians on the street below.

‘It was hugely complicated,’ says Martin. ‘We carried out detailed analysis with Laing O’Rourke and the cladding and steelwork subcontractors to work out the assembly sequence and how to hoist the units securely fasten them to the frame.’

Where the PFI model has often resulted in delays and inflated costs on NHS hospital projects, here the benefit of early contractor involvement gave reassurance of buildability and helped reinforce the prefabrication strategy. As a result the Cancer Centre was delivered on time and to budget, potentially signalling a new direction for UK healthcare design able to meet the needs of patients and project stakeholders.