The Spatial Organisation of Informal Urban Economies and Their Architectural Implication in Kano Old City

Informal economies constitute the backbone of commercial life in many Nigerian traditional city cores, and their spatial organisation within historic built fabric creates both a design challenge and a heritage conservation concern that requires empirical investigation to inform sensitive planning intervention. This study empirically investigates the spatial organisation of informal commercial activities within Kano Old City, analysing how these activities occupy, adapt, and transform the traditional built environment, and what architectural implications arise from this occupation for heritage integrity and spatial functionality. A mixed-methods empirical approach combined GIS-based spatial mapping of two hundred and forty informal commercial units, analysis of occupancy patterns relative to street hierarchy and proximity to formal market nodes, structured interviews with eighty informal traders, and physical documentation of architectural modifications made to accommodate informal commerce. Land use transition analysis using sequential satellite imagery tracked spatial changes between 2015 and 2023. Results demonstrate a clear hierarchical spatial logic in informal commercial occupation, with highest density concentrations at street intersections and market perimeter zones, and secondary clustering along pedestrian desire lines between residential quarters and formal market facilities. Architectural modifications including doorway widening, facade display structures, and canopy extensions are spatially concentrated in buildings within forty metres of high-activity nodes. Heritage impact assessment of these modifications reveals a spectrum from low-impact reversible adaptations to significant structural interventions that compromise original fabric. The study proposes an informal economy architecture compatibility guideline for the Kano Old City Conservation Area Plan. Keywords: informal economy, spatial organisation, Kano Old City, architectural modification, urban heritage.