The politics of prison buildings is dominated by discourses of novelty, innovation and the promise of the ‘new’. Public scrutiny is inevitably drawn to the opening of new establishments, but this is one fleeting chapter in the lifecycle of prison buildings as they are slowly pulled apart by the oppositional forces of creativity and entropy. In this chapter, I explore the processes of adaptation, obsolescence and destruction that press upon even the most formidable carceral structures. I build the case for a sociology of prison buildings, and I present findings from a thematic analysis of qualitative interview data that reveals how the dynamic encounters between humans and buildings shape the politics of prison building programmes over the broad sweep of historical time. I conclude that the penal states’ capacity to punish is never static and unchanging but constantly evolving in response to the way value is assigned to buildings as they age.