From maximum urban porosity to city's disaggregation: Evidence from the Portuguese case

When relating to build environments, porosity refers to soft transitions across geographies and to the interpenetration between spaces of a different character. While its importance is recognised, its absence in post-modern urban fabrics has become evident. Therefore, this paper's primary objective is to contribute to the resettling of porosity in its various dimensions. To that end, it questions the circumstances that led to the erosion of porosity in urban environments and how that erosion is visible. To answer, the paper (1) establishes concepts for urban and architectural porosity, the criteria that determine each of those and parameters to evaluate it; (2) revisits modernist principles, indicating those that contradicted porosity; and (3) demonstrates how porosity evolved through a comparative of five Lisbon neighbourhoods. The study attests that the implementation of ideas from the modernist movement resulted in a radical loss of porosity, concluding that, in maintaining modernist principles, Portuguese regulation keeps encouraging impermeable cityscapes. The research withdraws the term porosity from ambiguity. And presents concepts, criteria and evaluation parameters that are applicable in various contexts. Through an understanding of the problem, it also points towards a solution, highlighting the need for a further investigation to improve legal frameworks.