How can civil society, businesses, and policy makers at all levels of government scale up climate solutions to transform our cities? Discussions on low carbon urban transitions are often focused on hierarchical ideas about scaling up in a linear manner and emphasize socio-technical innovation and market take-up in sustainability experiments. Looking beyond commercialization, this paper together a wider range of political and cultural dynamics that have the potential to influence the impact and scope of zero carbon interventions. Drawing from relational scaling and embedding theories in human geography and urban studies, as well as the political dynamics of scaling from political science, this paper develops a conceptual framework that furthers our understanding of how catalytic change can be triggered in ways that build enough momentum to reconfigure urban systems towards decarbonization. This framework will then be applied to an analysis of a residential building retrofit case study in Canada. Society will not reach climate targets without substantially retrofitting buildings. Yet, building retrofits to increase energy efficiency and enable decarbonization have been difficult to implement effectively. They have been a particularly challenging climate solution to implement despite the fact that they can realize greenhouse gas emission reductions more quickly, are cost-effective compared to other climate change mitigation actions, and can be achieved using existing technologies. There is also no clear understanding of how to achieve the transformation this sector requires without exacerbating the challenges of energy poverty and gentrification. By examining a case study of residential building retrofit policies and experiments and analyzing gaps and opportunities to trigger catalytic change, this work in progress aims to addresses questions about accelerating just climate solutions to transform our cities.