Sky Gardens, Public Spaces and Urban Sustainability in Dense Cities: Shenzhen, Hong Kong and Singapore

This paper studies the spatial characteristics of sky gardens as public spaces to explore their potential to support urban sustainability in dense cities. This research understands public spaces as spaces that are open and available in different levels of access and use. The research focuses on 982 sky gardens in Shenzhen, Hong Kong, and Singapore. It adopts a mixed methodology, including site visits and observations, statistic measurements (based on SPSS software), and Grey Relation Analysis (GRA) methods. The research follows three steps: first, it studies the urban context, including urban density, land uses, and policy regulations regarding sky gardens and sustainability. Second, it examines sky gardens’ spatial characteristics in terms of form (morphology, typology, size, affordances, configuration), openness quality (accessibility, ownership, permeability), and geometry (open space ratio, height of space-to-building, void-to-solid ratio, shape index). Third, the research compares the findings in three case cities and discusses their potential to support urban sustainability. The results suggest that despite the limitations of sky gardens, they may play, to different degrees, fundamental roles as open public spaces in high-density urban environments supporting cities’ sustainability. High-density environments offer more opportunities for the sustainable development of sky gardens, which creates a new spatial paradigm for compact vertical greenery in high-density cities.