The Impact of material expression at entrance thresholds on invitation to access: a comparative study of shopping malls in Colombo, Sri Lanka

Abstract

Entrance thresholds in contemporary shopping malls function as critical interfaces between urban public space and privately managed interiors. Previous studies have examined shopping malls in relation to circulation, branding, and commercial performance. But limited research has focused on how material expression at entrance thresholds influences perceived invitation to access. This study investigates the impact of material expression at entrance threshold on invitation to access in two contemporary shopping malls in Colombo, Sri Lanka: Mall A and Mall B. Two ground floor pedestrian entrances from each case study were analysed using a comparative case study approach. Material expression variables, including façade transparency, threshold framing, material contrast, and volumetric presence were documented through structured architectural observation. Spatial visibility was examined using Visibility Graph Analysis in DepthmapX to assess visual integration and connectivity. Invitation to access was evaluated through perception-based surveys capturing legibility, spatial clarity, and social openness. The findings reveal a consistent relationship between strong material expression, higher spatial integration, and stronger invitation profiles. Entrances characterised by transparent glazing, clear framing, and visible interior volume demonstrate higher visual prominence and perceived openness. In contrast, entrances with reduced material differentiation exhibit lower integration values and weaker invitation perception. The study positions material expression as a spatial mediator that shapes both visibility structure and perceived accessibility at the building threshold. These findings contribute to architectural understanding of threshold design within dense urban retail environments.