Revitalising London's fifth elevation - its rooftops
16th March 2015
As we build taller in London and views across the city are created from more vantage points, the capital’s messy, uncoordinated roofscapes become a visible part of the city. An interesting, chaotic juxtaposition of roof forms and modern plant enclosures maybe, but perhaps inevitably this layer of London is treated as an afterthought and its potential not fully explored. As the pressure on space increases – particularly for high-quality offices – how do we negotiate planning, technical and urban issues to create not just adjuncts to existing structures but desirable, architecturally-exciting additions?
In the West End the ‘roofscape’ sits somewhere between 7- and 10 floors. From elevated positions one is acutely aware of this invisible, surprising layer of the city; this visual hotchpotch ranges from traditional mansards to ’80s pediments and recent additions, with long views to landmark buildings and the City of London skyline beyond. These rooftop accretions seem not to be informed by neighbourhood or building typology, creating a homogenised urban scene.
The demand for more space for living and working is apparent everywhere and the limited availability of new-build opportunities means that roof extensions and incremental changes to the roofscape continue apace. The current trend towards ‘office to residential’ conversions further concentrates demand, exacerbating competition for good quality workspace. The opportunity to realise the potential of the ‘roofscape zone’ to allow for growth has been suggested by others as an altenative to more obvious incursions into the skyline. The fact that upper level space with access to external terraces and panoramic views is at a premium creates a conundrum when working with older buildings originally designed with attics/ mansards, degressive proportions and constrained ceiling heights.
Our recent proposal for Aldwych House gave us the opportunity to engage with this context and consider an original approach to London’s roofscape. Working with client Rowan Asset Management, the challenge was to make a proposal to extend the 1926 building which forms part of the Aldwych ‘D’ opposite Bush House. The project forms part of a comprehensive refurbishment of the building and the addition of a rooftop ‘eyrie’ would add to the building’s appeal alongside the new Roka restaurant now installed at ground floor.
Equally, shifts in work patterns now mitigate towards greater spatial diversity in working environments. Alongside efficient deskspace, occupiers want to see great amenity spaces to promote collaboration and exchange of ideas, with flexibility to accommodate meetings presentations and events – perhaps just some relief from screen based tedium! Standing on the roof at Aldwych we immediately saw the potential to make a different kind of space which exploits views towards the river, framing panoramic views between the City and Westminster
Aldwych and Kingsway - originally planned in 1905, and not fully completed until the 1930s, was a bold and uncompromising masterplan which swept away a network of tight streets to form London’s most authentic urban boulevard bounded by much larger buildings that now frame St Mary le Strand Church. Today that context is evolving in and around Aldwych, driven by the redevelopment of Citibank House as ‘W’ hotel and proposals for the LSE and Arundel Great Court nearby – all of which exploit the roofscape in some way. The Garden Bridge will increase footfall in the area now branding itself ‘Northbank.’
However, realising a rooftop project such as this involves numerous challenges in terms of the building structure as well as planning restrictions. In general, this type of proposal is constrained by planning considerations which tend to limit increased height and bulk either directly through strategic views and tall building policies, or indirectly as a result of the conservation areas and listed buildings which proliferate in the West End where wholesale changes are usually considered inappropriate. This was the case at Aldwych which is a building of merit within the Strand conservation area, and therefore subject to policies which presume against further extension.
The building has a classical facade forming part of the elegant Aldwych cresent, although this form results in an irregular shaped building cheek by jowl with adjoining buildings to the rear. Previous adaptations had modified two lightwells, as well as forming an atrium and new lift core and an extensive mansarded plant enclosure. This agglomeration, whilst only slightly visible from the street forms a lopsided composition which detracts from the original architecture and adds to visual chaos in the roofscape. The original mansard roof is truncated and is terminated by a functional steel handrail.
An initial proposal consisting of a curving flat-roofed pavilion was discarded in favour of a bolder, more contemporary and integrated design. The symmetrical form of our design responds to the classical proportions of the front elevation of Aldwych House, creating a unified composition, and adapts to a more organic form in plan to negotiate the irregular shape of the building. The geometry was generated from logical springing points of the existing structure and ensuring key heights and consideration of rooftop views from adjoining buildings. The dramatic pavilion-like structure, made up of a series of geometrical-folded zinc forms, is perched delicately on the building’s mansard roof, with the design improving the proportion of Aldwych House and making it consistent with neighbouring rooflines.
It’s interesting that this freeform architectural language, more often associated with standalone iconic architectural forms, was generally considered as interacting well with an historic building and was instrumental in achieving planning permission in September last year.
This approach of a carefully composed roofscape suggests that a more creative approach to the rooftop architecture could unlock the potential for a different type of architectural space that is consistent with the fast-changing tenant profile in the area. Rooftops are a major consideration of London’s perpetual renewal, playing a part in the changing perceptions of neighbourhoods, as buildings are re-purposed and complemented. The ‘roofscape’ is an opportunity - not just to build more floors like-for-like but also to create additions of a distinct quality that surprise and delight.