The project is for the construction of a new 800 m2 house on an enclosed back-land site in Notting Hill, London, for a family of two academics and their two children. The clients had previously lived in typical London vertical town houses of up to five stories, and wanted the house to be connected and interactive by being more horizontal. The brief required a very private house for the family to live and work in, a suite of living rooms, a kitchen, two studies, a library, dining room, chapel, five bedrooms and bathrooms, a swimming pool, courtyard gardens, garage, wine cellar, laundry rooms and plant rooms.
We worked for over a year with the client to find the plot of land which with the restrictive planning laws in the UK would allow a contemporary structure to be built. We had experience of working with back-land sites (essentially redundant factories or warehouses in residential areas) in London, and concentrated on these in our search. The site we eventually found was ideal as the planners would only allow a single house on the site and was very well located in an area well known to the clients. However as is typical of back land sites, there were problems of access, overlooking and overshadowing to overcome, as well as a requirement for fourteen different party awards with neighbouring owners.
Design Process (see images in ’Design Process’ folder)
Traditional design processes tend to start with the design, then evaluate their success. This will often lead to inaccurate assumptions and is prone to preconceived thinking. We realised very early on in the design process that this site was intrinsically linked to the surroundings by daylight, sunlight and view criteria which change throughout the seasons, and these dominated the design approach. Our aim was to attempt to avoid falling into 'default' solutions to this design problem through a process of detailed analysis of site and brief prior to any design phase. Following earlier research work carried out at the Architectural Association School of Architecture in London into computationally generated solar form, which is inspired by the morphogenetic processes of nature, we have built computational models that, through a 'generate and simulate' cycle, are able to explore the space and optimise potential proposals.
The orientation of the site runs almost east-west, and looks towards the more open sides of the site to the south. However, the site is heavily overlooked and overshadowed on the south and west elevations and it was critical to maintain privacy, whilst optimising daylight and sunlight penetration into the house, as cultural opacity in the UK demands sun and daylight to enter the site, to be redistributed, to be contained, and to change perceptions about life in London.
We were trying to create an architecture of local adaptation. We defined a general framework that held everything together (not physically; more visually), but that also allowed everything to change depending on the local as well as the global environment. Our framework ended up being a 3d grid which itself became adapted to the local and global environment - the grid spacing, the angle of the roof, etc. Nature is similar. The animal body plan which is the same for so many animals is the framework. Based on this framework, nature can adapt the animal (ie materials and shapes within the framework) to completely different environmental condition. The environment includes constraints (e.g. design requirements such as daylight levels) and context (e.g. a neighbouring building), and there are local and global versions of both. In addition, the environment also includes what in biology is referred to as internal environment - how one part of the design may affect another part.
Our starting point therefore was to represent the empty volume of the site as a three dimensional grid of voxel data points (3d pixels) each consisting of a range of varying attributes. Working with the environmental engineers, Arup, a detailed environmental analysis for each individual voxel on the site was carried out. This analysis produced a database of solar and daylight conditions throughout the year, taking into account weather patterns specific to London. Such environmental data is large and complex and therefore the computer becomes an ideal tool for hypothesising and extrapolating possible proposals. Database mining software tools for the extraction of generalised conditions and conclusions from the environmental data were developed by ourselves, as well as a number of visualization tools to understand the data more fully. Some critical discoveries were made during this period which greatly influenced the final form of the house.
Subsequently, the client’s preferences and lifestyle were superimposed onto this environmental data. This led to the emergence of a project that was tuned to both the three dimensional environmental conditions and the brief. The section became inverted, placing the bedrooms on the ground floor and the living spaces on the first floor, essentially a double height ‘piano nobile’. The inward looking nature of the site in conjunction with the inverted section led to the development of a completely glazed 'sky facade' roof to the house. This 'sky facade', the only visible facade, was seen as an environmental moderator, filtering sunlight and daylight through layers of transparency and opacity. Three different densities of fritting were allocated to the roof panels according to criteria from the rooms below. Solar optimised terraces and gardens created internal courtyard volumes into which the surrounding spaces face.
Structure The empty site was essentially a box 40 m deep by 15m wide 10 m high on one side and up to 8 metres high on the other sides, consisting of brick party walls. We were not able to apply any pressure to the party walls having to build an entirely independent structure, and had a requirement for very large planes of walls extending up to the top of the 10m high wall.
In situ exposed concrete was a natural choice- it acts as an environmental moderator (the house is naturally ventilated), the exposed finishes put workmanship on display, and structurally there was a requirement for large vertical cantilevers and beams. A grillage of deep tapering beams span from vertical cantilevers 8m-10m high and 32m long, forming the high level enclosure to the room below. These ‘rooms’ range in size from 18m x 3m at the largest to 3m x 3m at the smallest.
The complexity of achieving this apparent simplicity was deceptive. 14 separate party wall awards were required and the site is only accessible through an arch 3m wide and 4m high. The vertical cantilevers needed to be built within 150mm of the existing walls, and no pressure could be placed on the party walls during construction. Our subcontractor developed a method utilising specially designed and fabricated steel shuttering at the back of the wall taking the forces through to the front of the shuttering, which was propped back onto the slab. Due to the restricted nature of the site, the project had to be built from the back of the site in stages towards the front of the site, as mobile crainage was the only solution possible for placement of concrete and movement of shuttering.
Careful research on the concrete specification was carried out by ourselves, Arup and the client- whilst concrete was an early decision, there were concerns relating to achieving the finish and colour required. Site visits from London to Berlin were undertaken in order to narrow down what was wanted, and possibly more importantly, what was not wanted. We were looking for an ‘as struck finish’ with no making good. Some character was also a requirement, rather than a very flat even colour throughout. These are issues that are subjective and therefore difficult to include in a specification. The solution was to research the methods used in the concrete we did like, and write the specification from that point. Trial panels were specified, and the basement walls used to test various chamfer and bolt hole details, as the evenness of the bolt holes both in finish and setting out were very important.
Environment The house in naturally ventilated, which is controlled by means of thermal mass, shading, and air movement.The roof, although made of 300m2 of glass, has a highly effective solar coating, three different frit densities to the glass, electrically operated blinds, and opening vents, all of which contribute to a high level of control of the internal environment by the occupants.
Materials A very restricted palette of materials was used throughout the house, consisting of stainless steel, concrete, glass and aluminium. Polished concrete screed floors, stainless steel lined swimming pool and bathrooms, exposed concrete structure to the walls and beams, stainless steel kitchen, aluminium framed sliding doors and windows, perforated corrugated stainless steel used as cladding and external screens and doors.