What is Urban Depth?
Urban Depth is a term describing the city in all of its richness and complexity. It encompasses all the components of urban space from the street, to the façade, through the section of the building, block or neighbourhood, and out the other side.
Urban depth is a structure, present in buildings, blocks and cities, whereby spaces are differentiated into zones characterised by different norms of decorum, privacy and access. Implicit awareness of these zones, and the boundaries between them, coordinates where people go and what they do in architectural space, both individually and collectively. It is both the spatial configuration as well as the structure in which civic, social and economic life takes place. Urban depth is a term coined by Peter Carl which describes the city in a way which takes into account this richness and complexity. [1] The concept was extended by Jane Clossick to argue that urban depth consists of a ‘depth structure’. [2]
A depth structure is a system of social territories, which contains and reproduces knowledge that enables spatial co-operation. Depth structures are organised in a way which demarcates a system of discreet territories, or zones, with clear thresholds between them. These co-created configurations structure people’s behaviour. In addition, the physical expression of depth structures through architecture and objects both creates social life and is created by it: social behaviour and spatial organisation co-emerge. Depth structure, therefore, mediates between the physical world of architecture and the knowledge of the individual. Such knowledge is embodied, or tacit, and is externalised by human beings into the built environment in order that it can be shared, even amongst strangers, using the system of zones and thresholds.
A depth structure is composed of multiple discrete zones, each with its own unique decorum, norms and expectations of behaviour. The idea of decorum grows from the Husserlian concept of doxa in which what is taken for granted in social life and how people know where they can go, how they must behave, what they should wear and who they may speak to. Doxic knowledge is encoded in the zones in depth structure: there is a specific set of possibilities for human action available in each zone, described by Vesely in his notion of ‘situation’. [3] Some zones are very public, such as a high street pavement; others permit only people with certain characteristics. The way the decorum in a zone is communicated is through decorum indicators, which may include gatekeeping and other people’s behaviour, décor and signage. Decorum indicators are culturally specific, and interpretation of them requires knowledge gathered over a person’s lifetime, both from personal experiences and from absorbing the traditional knowledge of the culture. In each zone the decorum is different and communicated by the people, architecture and objects of that zone, and the decorum changes between adjacent zones.
Where zones meet are thresholds, which are social boundaries defined physically by boundary conditions. The threshold is the place where the decorum of one zone shifts to the decorum of the next, and the boundary conditions may include, although are not limited to: fixed elements such as walls, windows and doors; moveable objects such as furniture, screens and freestanding signage; surface treatments such as wall mounted signage, decorative finishes and lighting. The physical delineation of zones and thresholds through architecture serves a communicative function, offering information which allows people to decide whether they are permitted to cross thresholds and the appropriate decorum to adhere to if they do.
[1] Carl, P. (2011) ‘Type, Field, Culture, Praxis’, Architectural Design vol. 81, no. 1.
[2] Clossick, J. (2017) ‘The Depth Structure of a London High Street: A Study in Urban Order’, PhD Thesis, London Metropolitan University.
[3] Vesely, D. (2006) Architecture in the Age of Divided Representation: The Question of Creativity in the Shadow of Production, MIT Press.
[4] Clossick, J. and Colburn, B. (2021) ‘Design Precepts for Autonomy: A Case Study of Kelvin Hall, Glasgow’ in Architecture and Collective Life, Routledge (forthcoming).