Nairobi’s planning regime is characterized by two conditions of exception: on the one hand, exceptions from regulation, that is, planning offices granting exceptions from planning rules and, on the other hand, regulatory regimes that are enforced by low-level administrations outside the planning office but that significantly impact Nairobi’s urban space—we call this exceptional regulation. We argue that it is these two intertwined conditions of exception that make possible the building of shiny modern city as well as the provision of essential urban services. We examine the two conditions of “planning by exception” by analyzing a scrap heap that has endured in central Nairobi for over a decade, even as the neighborhood around it has radically changed. The position of the scrap heap makes the contradictions of this regime of planning particularly visible. On the one hand, the construction sites dotting these neighborhoods provide a wealth of scrap for dealers to gather—and dealers, in turn, provide an essential recovery service. On the other hand, in these increasingly exclusive spaces, businesses like scrap metal heaps are no longer welcome. Thus, the construction boom simultaneously grants scrap dealers opportunities for accumulation and makes the conditions of that accumulation highly uncertain. This scrap metal heap thus offers important insights into Nairobi's spatial regulation because it is both a leftover from the neighborhood’s earlier socio-spatial form and intricately entangled with the redevelopments currently reshaping the city. Our key contribution is that we can only understand urbanization of Nairobi—and other postcolonial cities—if we understand planning as simultaneously working through a regime that grants exceptions to formal planning and by employing exceptional regulation of marginalized spaces.