London. 2007

  • Project Details
  • Completion: 2007
  • Cost: £37 Million
  • Clients: First Base Ltd & The Blackstone Group

KX200 investigates a way to reinvent out-of-place towers and, in so doing resolve their tabula rasa-like condition. Two redundant office towers – stripped back to their frame – have been set into a new five-storey podium which responds to the scale and character of the surrounding streets. The lightweight filigree pattern of perforated steel and glass of the towers’ façades complementarily counters the super-scaled concrete cladding components of the podium. The horizontally layered amalgam of 846 student rooms, 50 market and 14 affordable apartments, offices, retail and private and communal courts makes this a new mixed-use model for London that describes the commercial, environmental and architectural potential for re-using structures.

KX200 is the redevelopment of three existing buildings on Pentonville Road, Kings Cross, into a mixture of student accommodation, private and social housing, retail and office space. KX200 was a project with an existing planning consent and a ‘parent’ developer when First Base and the architects were invited to investigate where both architectural quality and financial value could be improved. KX200 has been a very rapid project, requiring the team to re-think the usual design & construction sequence, as well as re-thinking the traditional model of student accommodation. The £35m build was completed at the end of 2007.

The architectural expression of the development’s varied functions was key to the design of the building and the negotiation of planning consent. The idea of the horizontal ‘city sandwich’ of different uses layered on top of each other provides a variety of street level activity arranged around the site. The locations of different residential and commercial entrances were tuned to compliment the different characters of the surrounding streets. The retail units, student entrance and new hotel-like reception area are located on Pentonville Road marked with a huge double height portal and semi-private entrance courtyard. Less busy private and social housing entrances are positioned on the quieter side streets: Killick Street and Calshot Street. These share a residential character now reinforced by the new development, as they lead away from the main road towards Tecton’s Priory Green estate.

The new five-storey podium reinstates the city block’s building line to the three streets, and by mixing uses at street level, the scheme provides an animated streetscape with the advantage that 24/7 usage discourages anti-social behaviour and increasing security and a sense of community. 

In addition to the internal advantages of reuse, there is a marvellous extra benefit - the view enjoyed by the majority of KX200’s 16 floors. Double height plant rooms were demolished on top of both towers and replaced with two new floors of residential accommodation. The reuse of the frame is environmentally most advisable - less demolition spoil, and no materials or energy used to construct a replacement. It is also economically beneficial for the client to reuse the frame they have bought, rather than pay for a new one.

The ‘Nido’ concept provides private ‘halls’ accommodation to university students studying in central London. The scheme sets a new standard for student rooms and the 616 studios and 199 twin rooms have quality, designed interiors, free internet connection and floor-to-ceiling windows behind a safety screen. 

Driving the design was the desire to create different architecture for the two elements of the project – distinguishing podium from towers. The reused concrete frames of the office towers were re-clad in ‘lightweight’ glazed unitised curtain walling, re-inventing the traditional sober suit of corporate architecture with a light blue / mid-blue pattern. The pattern shows both a Part L limit on ‘vision’ glass (windows), and also the desire to change the façade from commercial office to a more suitable, playful character which has established the project as a new part of the King’s Cross skyline.

Meanwhile, the base of the building was clad with pre-cast concrete panels. This more solid, massive masonry material relates to the façades of adjacent buildings and the large panel modules a civic scale to Pentonville Road where they are stacked four floors tall, and a more domestic face to the social housing on Killick St, where the panels are limited to single-storey modules. The Techcrete panels have three colours, related to function: light grey for residential façades, mid-grey for community facilities, and black at ground floor retail areas. Upper panels are acid-etched to expose Mica aggregate, while the black Basalt aggregate panels at ground level are polished to lend a more opulent tactile quality akin to terrazzo.

The construction programme for the project was extremely fast – taking the design through planning and on to site in six months, and from demolitions to completion in another year and a half. Both the unitised blue curtain walling and the pre-cast concrete were mass-produced off-site in the UK, speeding the construction process and simplifying site works. Repetitive internal elements such as the student’s bathrooms and kitchen were also mass-manufactured and delivered full finished, ready to be plugged in and used.

KX200 embodies a much-vaunted but little-realised concept - that of the ‘mixed use’ building. Here the residential accommodation including private apartments, social housing, student halls of residence are located above, below and around offices, shops and restaurants to create a vibrant city block with a range of benefits for residents and the surrounding community.

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