Folding courtyard: layered evolution and micro renovation of the compound courtyard house in the southern inner city of Nanjing, China

Traditional courtyard houses in the southern inner city of Nanjing, China, have undergone significant transformation over time, evolving from single-courtyard structures to complex forms accommodating multiple households. Through processes of continuous expansion, compression, and spatial encroachment, a high degree of residential capacity and density has been stacked in these compound courtyards. Based on a close observation of everyday living spaces, this study interprets the complexity of existing compound courtyard houses, focusing on their layered evolution, overlapping space, and inward-folding interface. By proposing a new design strategy of micro renovation, the research introduces a lightweight and transparent interface to reconfigure fragmented yet densely overlapped domains, accommodating daily life and supporting activities, thus reinterpreting and reshaping a kind of co-existing courtyard for mixed-use residences.