Abstract

While vertical densification offers numerous benefits, it can also lead to environmental harm, damage to cultural heritage, increased housing costs and exclusionary gentrification, posing significant challenges for urban governance. In Chile, new progressive local governments are working to regulate vertical densification. This study compares the development paths of two boroughs: Valparaíso and San Miguel. By utilising official property datasets, density maps and qualitative data analysis based on semi-structured interviews, the study explores how previous market-orientated, laissez-faire vertical densification policies are superseded by stricter regulations driven by progressive local politics, under the promise of alternative, less-dense densification. The cases illustrate, in the first instance, grassroots mobilisation and judicial challenges that restrict vertical growth; and in the second instance, restrictions on density regulations that do not affect floor area ratios. The study reveals the limited effectiveness of these approaches, as they lead to either a shortage of affordable and social housing or exclusionary gentrification, despite the central government’s funding of social housing estates aimed at preventing this. Therefore, more comprehensive densification policies are essential. This case study highlights the fragile governance of vertical densification in Chile’s ‘progressive municipalism’, its centrality in the political trajectories of the boroughs and the challenges in reconciling local community opposition with the need for housing welfare under the (still neoliberal) market rule. © Urban Studies Journal Limited 2025