This paper is based on an ethnographic study of corridors in a large university building, originally built to house local government in the early 20th century. By attending to their huge physical presence in the everyday culture of an institution, the paper shows how corridors matter. Too often invoked as iconic, intangible metaphors, the presence of corridors as cultural materials can be forgotten. Conversely, as incidental – or even detrimental – remnants of past design trends, they are perceived parts of a divisive, hierarchical organisation of space. As the open-plan office, indoor street, forum and atrium displace them in a new design for ‘openness’, the study focuses on the mobilisation of corridors in the daily, sometimes momentary re-arrangements of meaning in an organisation. In conclusion, I discuss how the new architecture of ‘openness’ might be reconfigured through mobile understandings of everyday ‘openings’ and ‘closings’.