Introduction There is a substantial body of theory and evidence on the ‘rise’ and fall’, ‘trajectories’ or ‘dynamics’ of neighbourhoods, including areas dominated by private housing, areas with mixed tenure, and social housing estates. This chapter sketches out some of the main themes of the literature, focusing on characteristics and dimensions which can be used to define change over time, and the factors that may cause or prevent it.

What we know about neighbourhood change

Building age, deterioration and ‘obsolescence’

Buildings are a key part of neighbourhood infrastructure, and building deterioration is often seen as indicator, effect and cause of neighbourhood decline. Buildings deteriorate continually through use and the passing of time, in a potentially predictable way. It has been suggested that building age is a reasonable proxy for the quality of homes and environment (Leather and Morrison 1997). Deterioration can be prevented or remedied, at a price, though repairs. However, when repairs costs mount, or outweigh likely repaired value, or if a new land use might provide more net value in the medium term, buildings may become ‘obsolescent’ and be abandoned or demolished. In theory, designers and initial builders can create buildings that can adapt to all the potential uses they will be put to, which deteriorate slowly and which can be repaired easily and cheaply. However, ‘all buildings are predictions. All predictions are wrong’ (Brand 1994:178). Deterioration is likely to be faster where initial costs were emphasised over cost-in-use or life-cycle costing; where untested, unfamiliar designs, materials and components were used; design or construction were ‘poor’; use was ‘inappropriate’ or very heavy; or if there was insufficient maintenance. All of these factors apply to at least some social housing, and Prak and Priemus (1986) commented that much post-war social housing lacked ‘robustness’, the ability to cope with changes in use over time.

Building obsolescence, however, is not simply physical. It may be almost independent of age or the extent of deterioration. Obsolescence may be affected by social, economic and technological change. Demolition can be caused by changing land values, changing user requirements and the decay of non-structural building elements.