The Land-Use Transition to Rooftop Greenhouse Buildings (RGB): Economic Pull, Institutional Readiness, and a Seven-City International Comparison

Although rooftop greenhouse buildings (RGBs) have become multifunctional urban infrastructures that turn roofs into productive land, their commercial spread across cities remains highly uneven. This study examines that unevenness by reframing RGB diffusion as a land-use transition pathway shaped by the interplay of economic demand pull and institutional readiness. It develops this account as a proposition-generating typology rather than a statistical test. Methodologically, the study combines a qualitative thematic synthesis of the RGB literature with a comparative narrative analysis of seven cities across high- and middle-income tiers: New York, Paris, Singapore, Barcelona, Seoul, Bangkok, and Dhaka. The analysis describes an urban-agriculture intensification ladder on which high-intensity commercial RGBs emerge only above specific wealth thresholds. Linking this economic axis to two institutional channels—legal permanence and administrative agility—we construct a land-use typology in which a commercialization gate separates commercialized from research-stage RGBs. It also reveals South Korea as an institutional paradox, where world-class technology coexists with blocked regulatory channels. We conclude with a development-stage-differentiated, transferable land-use policy framework that helps planning authorities align institutional readiness with economic capacity while proactively mitigating green-equity risks.