As part of the proliferation of security concerns and privatization of space, the consideration of boundary walls in contributing to the publicness of public spaces is limited to their presence and level of visual accessibility. However, as one of the interstitial configurations of street edges, the enabling capacity of the physical attributes of boundary walls in influencing the perceived sociability of the adjoining space has hardly been investigated. The contribution of boundary walls towards the publicness of public spaces is dependent on the intensity of their physical attributes. Physical features, surface uses, physical access, and visual access conditions are the attributes of boundary walls that not only represent the intended levels of control, but also latently reveal the intrinsic association with the adjoining space. Premised on the interaction between objective and subjective measurements, in this study, these physical attributes of boundary walls are measured in terms of their contribution to the publicness of public spaces, while the perceived sociability of the adjoining space is measured through a questionnaire survey in positive and ambiguous space types. The physical boundaries of eleven positive spaces and twelve ambiguous space types in Tiruchirappalli city in the state of Tamil Nadu, India are identified, and the differences in the perceived sociability of the adjoining spaces are analyzed with respect to the physical attributes of boundary walls and the presence of sidewalk. This study has found that the physical features, surface uses, visual access, and the varying conditions of the abutting space of boundary walls influence the perceived sociability of the adjoining space.