Housing and the city. A spatial analysis of residential building activity and the socio-demographic background in a Mediterranean City, 1990-2017

Fluctuations in residential building activity are becoming progressively more intense over time and space in advanced economies and especially in Europe, fueling real estate market segmentation and making the performance of the construction industry increasingly unpredictable. If non-linear urbanization paths are the result of economic downturns consolidating progressively more volatile real estate markets, the present study investigates the impact of recent building cycles on long-term urban expansion in a Mediterranean city (Athens, Greece), using multiple clustering techniques run on a large set of building activity and socio-demographic indicators. Changes over time in building activity were evaluated considering 12 spatially-explicit indicators derived from the analysis of building permits released by Greek municipalities between 1990 and 2017. By referring to different analysis' scales (macro-scale: settlements, meso-scale: buildings, micro-scale: dwellings), indicators allow a comprehensive investigation of multiple dimensions and characteristics of construction markets at four-time intervals of 7 years each (1990-1996, 1997-2003, 2004-2010, 2011-2017). Spatio-temporal variability in building activity was further investigated considering 12 contextual indicators assessing the basic socio-demographic attributes of local municipalities. Cluster analysis allows identification of distinctive, local-scale responses of real estate markets to economic cycles (expansion-stagnation-recession) in both short- and long-term horizons and relate them to the dominant socio-demographic context. Density of new buildings, average floors per new building, density of buildings' additions and number of building permits per inhabitant were found to be the most sensitive indicators to economic downturns in the study area. Infrastructure-driven development, as a result of the 2004 Olympic Games, has produced relevant short-term alterations in residential construction markets, complicating urbanization trends at the local scale. Multi-scale indicators from building permit records provide a useful insight in the diachronic mechanisms of urban growth, with implications for regional planning and design of sustainable development practices.