This prefabricated modular system was first developed as a prototype for installation within courtyard houses in the traditionally Muslim district of Dashilar, in Beijing. The dense historic neighbourhood is home to disadvantaged communities who do not have the means to renovate the buildings. The Courtyard House Plugin initiative aims to upgrade dilapidated structures in an adaptable and cost-effective way, therefore both improving the residents’ living conditions and preserving the original architecture. The modules comprise the structure, insulation, wiring, and interior and exterior finishes in prefabricated panels. Installation and assembly takes no more than one day and does not require specialised labour. The Plugins represent a radically new approach to urban upgrading in China, where vast areas are regularly torn down. The central government approved the first two prototypes, and to date, some 15 houses have been upgraded.