The climate crisis has prompted new imaginaries in architecture and design that go beyond technical responses to issues of sustainability and into critical and creative practice. Recent discourse suggests that architects and designers can intervene in this cultural condition by constructing and materialising alternative realities. Models, as means of representation, hold particular promise for such intervention, as they can accommodate both theoretical concepts and material interventions. These concerns are explored through Under Construction, a design project that imagines a city that is constantly being rebuilt using a limited stock of materials. Consisting of a scale model of a neighbourhood constructed from demolition waste, the project explores how salvaged pieces of material can be situated in “real” material flows while simultaneously representing something other than themselves. The project argues that the ambiguities that the blending of the real and the fictional result in can unlock new possibilities for architectural representation.