Affordability pressures are increasingly forcing low income renters into substandard or ‘informal’ housing arrangements ranging from share accommodation through to backyard ‘granny flats’ and unauthorised dwelling units. This project aims to uncover how this ‘hidden’ housing is produced within formal systems of urban regulation, and risks or benefits for residents. By exposing the significant but often ignored role of informality within housing systems, the project expects to advance the fields of housing and urban studies; lead international scholarly collaboration; and build research capacity. Project outcomes are intended to enhance local planning practice and improve housing standards and choice, particularly for low income renters.