Density and design: the impact of urban densification on design qualities in residential neighbourhoods

This study is focused on the concept of urban intensification, investigating the costs and benefits of higher density urban development. It attempts to define the exact physical patterns and spatial characteristic of the density of residential urban areas in order to establish the extent to which design qualities are delivered or compromised in high density urban form. In this way, the study attempts to identify any interrelationships between three factors: urban density, urban layout and urban design quality; and to see whether there is a consensus that higher density is linked to changes in urban layout, and has consequences in terms of urban quality. The study covers these three concepts at two spatial scales, namely the urban block and the neighbourhood. The work demonstrates that significant changes in morphological patterns such as plot size or control and ownership of open spaces, result from higher density design and, that there are subsequent impacts on particular design qualities such as overall adaptability or biodiversity of the residential neighbourhood. An analytical framework, elaborated from the theory, was developed taking into account appropriate measures of urban density (e.g. people or built form density measures), descriptors of urban morphology (e.g. average size of plots and open spaces), and indicators of urban design quality (e.g. mixed use ratios, levels of diversity in house types and sizes). The methods of analysis and testing of the theoretical proposition include, first, the use of computer simulation of urban tissue prototypes in three defined ranges of density; second, testing the acceptability and preferences of design typologies via focus group discussions with designers, developers and potential local users. Finally, this research develops a transferable method for defining and measuring design qualities which are important for specific localities, a method which can be used to evaluate possible emerging urban typologies in high density residential schemes