Under Construction imagines a city that is constantly being rebuilt using the same stock of materials. Reuse of building materials is not just a problem of logistics and material flows. It is as much a cultural and architectural problem. One of the most persistent architectural conventions is to consider abstract space before objects and materials. Building elements and furnishings should be subservient to a larger whole. This approach is aligned with a view on the world that is inherited from industrialism, in which any materials could be sourced anew and moulded into shape indefinitely. Reuse, as a conceptual approach to architecture, is different in that the starting point is a specific and limited stock of elements and chunks of materials. Each piece of material comes with a set of qualities – a character – that may be amplified, subverted or altered. In addition, depending on the relation between the context of the original structure and the new structure, reused objects may be charged with different cultural value and meaning. Under Construction is a fictional neighbourhood constructed from discarded building materials. It begins with a scavenger hunt where we visit demolition sites and collect building materials: fractions of concrete, asphalt, shards of glass, fragments of window frames, bits of plasterboard, plastic piping, and so on. By playing with the scale of this kit of parts, we imagine a neighbourhood constructed from reused materials. Armed with hot glue guns we erect a bustling city with a rich and varied materiality. As structures grow, interiors, furniture and infills between fragments are created from recyclable filament using off the shelf 3D printers.