Technical and Practice, High Rise Housing
The Architect's Journal, 3rd November 2011With its rampant four-storey cantilever, Proctor and Matthew’s tower overlooking the Olympic Park has made regeneration fun, writes Felix Mara.
Proctor and Matthews Architect’s Lett Road apartments, completed in September 2010, might be a bold and uncompromising building, but it also had the full blessing of the planners. The East London borough of Newham’s policy was to encourage intensification of the site, which is just off the main approach road to Stratford. By building to a height of 12 storeys, it has been possible to fit 64 mixed-tenure apartments (including 10 affordable units for the Guinness Trust), and to provide a landmark overlooking the Olympic Park. Thus it combines Newham’s targets to increase densities and to regenerate an area characterised by disused industrial buildings and low-quality housing.
Newham also wanted the development to relate to the immediate streetscape of two- and three- story buildings, and Proctor and Matthews responded by articulating it has two interlocking elements: one L-shaped, five storeys high and mainly brick-faced; the other rising to 12 storeys and zine-clad, with a four storey cantilever. “We were excited about the cantilevers,” says Price & Myers associate Tim Wainwright, putting paid to the notion that all structural engineers are intent on sacrificing architecture on the altar of efficiency.
There is no structural rationale for the cantilever. It may reduce vertical loads on the foundations below the south façade, but overturning forces acting on the inboard foundations, generated by the cantilever, dramatically offset this reduction – it would have been much more efficient to transfer loads to the substructure by direct vertical paths. Price & Myers carried out finite element analysis of the cantilever, producing separate models of isolated areas of interest. There was no BIM model, although Price & Myers used Revit software, with data imported from Proctor and Matthews’ MicroStation files to model and remodel the cantilever. “When the cantilever was de-dropped, there was a ridiculously small amount of settlement – about 3mm,” says Proctor and Matthews associate Georgina Bignold.
The back-spanning components of the concrete frame, which connect with 300mm-thick core walls, were difficult to co-ordinate with the windows, and the height of the space below the cantilever (plus the wedge of dead space above it) took out two flats. To use a phrase often repeated in the Arup Journal, the cantilever was there “for architectural reasons”. It was also there because Newham liked the way it addressed the A118 while leaving the L-shaped block alone to deal with Lett Road and Jupp Road. Developer Thornsett’s initial enthusiasm for the cantilever waned when Price & Myers explained the full implications, but they stuck by Proctor and Matthews’ concept. “When contractor Lancsville went into receivership, Thornsett took over and micro-managed the subcontractors,” explains Proctor and Matthews director Andrew Matthews.
The L-shaped block adapts to the scale of the side streets by juxtaposing a range of finishes and window styles. – some punched into brickwork and others more flush, within areas of composite aluminium sheet cladding and vertical over plates. Proctor and Matthews originally proposed opaque glass and timber, but only one instance of this survived value engineering. The massing is also animated by balconies and perforated sheet-clad oriels, which required meticulous co-ordination with the structural core. Whereas the balconies have horizontal, thermally broken Schott connections, the oriel windows have simple bolt connections with neoprene joints. “To protect children from falling, the top of the guardings are 800mm above the window ledges, and will therefore be at some people’s eye level,” says Bignold.
Procurement was Design and Build, but Proctor and Matthews produced Stage F drawings that worked through waterproofing, insulation, ventilation and fire safety problems. They were then novated to Lanscville. “Thornsett was quite clever,” says Matthews. “They knew that if we only took the drawings to Stage E, the design quality would suffer because there would be too much room for interpretation.”
Layouts follow the guidelines set out in the National Housing Federation’s Standards and Quality in Development: A good practice guide. “The scheme also followed ‘Secured by Design’ principles, with a clear definition between public communal and private realm space, and street-level entrances to the units on Lett Road,” says Bignold.
The development will benefit from the Greater London Authority’s plans to make landscaping improvements to the adjacent disused Charterhouse river, forming a new linear park connecting to Stratford Station. ”The GLA was very supportive of our design approach, but felt that what we were doing should inform the surrounding development,” says Bignold. “So they asked us to produce an urban design study for the sites immediately adjacent.”
This is not Proctor and Matthews’ most dainty building, and it isn’t trying to be. There is a touch of the Stirling and Gowan about it, especially in the geometry of its rampant cantilever. But along with the Brutalist overtones, its rooftop playground and sheltered courtyard bring humanity, and a sense of fun.