Recent conceptual debates within carceral geography about spaces of detention have largely dismissed Goffman's micro‐level analysis of closed spaces and interaction. As a response to Baer and Ravneberg's 2008 contribution to this journal on the inside/outside of prisons and the importance of indistinction, with its critical view on Goffman as a thinker/scholar of relevance to studying carceral geography, this article aims to re‐engage with Goffman's Asylums in order to establish its applicability in terms of both theoretical and substantive implications for this sub‐field. The concept of heterotopia, introduced by Baer and Ravneberg as a neo‐institutional alternative to Goffman's theory, will be addressed in its relevance to understanding spaces of confinement. The empirical material is part of a research project about young women's experiences of closed institutions in Scotland, specifically prison environments, secure care and closed psychiatric units. Their descriptions of being locked up and their emotional, symbolic and embodied ways of understanding and coping include entangled encounters with closed or “total” space that show elements of spatial semi‐permeability. This spatial state can be understood as partially open, allowing the passage of certain elements while acting as a barrier to others, and it can be found in Goffman's account of the total institution as well as in Baer and Ravneberg's experiences of prison. The semi‐permeable nature of space in a closed institution – including its dimensions of inside and outside – does not become any clearer by postulating an empirical and theoretical juxtaposition between distinction and indistinction. An in‐depth engagement with Goffman's insights into the micro world of a closed institution instead offers surprising contributions to the understanding of semi‐permeable insides and outsides.