Building upon conceptualisations of the sexualisation of space, this paper interrogates the ways in which heterosexual discourses are produced, enforced, legitimised and maintained as dominant within student accommodation. Analysis is derived from interviews with 17 gay male undergraduates attending a UK institution. I detail the micro-level processes, as framed by dictums of hegemonic heterosexual masculinities, by which participants' male flatmates reinscribed the heterosexual matrix in their living spaces. I then deconstruct how they safeguarded it through their verbal and physical regulation of alternate sexualities. Some participants contributed to the maintenance and validation of this heteronormativity in downplaying, justifying and not challenging flatmates' behaviour which could be coded as anti-gay. I therefore position student accommodation as a key site for the socio-spatial production of the heterosexual matrix and reinscription of heteronormativity, as construed through the workings of assertion, regulation and consent.