14. Typo-Morphological Analysis of Housing Layout and Density in Tehran

This research provides a historical analysis of morphological changes in housing in Tehran, as they have been constrained at each successive period in the city’s growth. The research aims to understand this evolution by investigating the relationship between housing typology and urban morphology. A GIS analysis is made of plots, buildings, and blocks in three areas of the city representative of significant stages of development. The analysis focuses on five topics: (1) the question of block size and shape, (2) configurations of plots within blocks, (3) pedestrian and vehicular access, (4) provision of open space around dwellings (ground coverage), (5) natural lighting. The argument of the chapter is that, in the transition from courtyard houses to narrow row houses and later to row apartments, and besides cultural conceptions and the effects of land value, are the constraints imposed by certain ‘generic functions’, most importantly access (pedestrian or vehicular) and day lighting. This transition is arguably the result of limits imposed on frontage width, which have their origins in the provision of street access to each plot of land in the first phase (from courtyard to row houses); and in the second phase (from row houses to row apartments) the need for more houses and higher densities. The conclusion from the analysis is that although many different cultural, social, physical and environmental factors are involved in the evolution of housing, which should not be treated simplistically, these basic generic functions—such as vehicular access—can dominate all other considerations in defining a new type.