Urban areas are increasingly failing to provide citizens with adequate and quality public open spaces. In this regard, Hong Kong characterises an extreme condition with 2.7-2.8 m2 of open space per capita. The burden of this scarcity falls most heavily on economically disadvantaged social groups, such as migrant domestic workers. In this context, grade separation pedestrian systems that were originally designed for mobility purposes, can provide space for sociability-oriented stationary uses. This study finds that the density of stationary activities in a typical elevated pedestrian network is as high as 1.2 person/m2.