House On The House / Wutopia Lab

Architects: Wutopia Lab
Area: 39 m²
Year: 2015
Photography: Yijie Hu
Lead Architects: Yu Ting
Design Team: Xia Murong, Ge Yufei, Wang Suyu, Liu Qicai, Yu Junfeng
EPC: PSA Associate
Project Type: Residential Renovation, House Extension
City: Number 23, Lane 389, East Jinling Road, Shanghai
Country: China

House on the House, designed by Wutopia Lab, is a 39 m² residential renovation of a former water tower in Shanghai, China. Originally constructed in the 1920s and rebuilt in the 1980s, the deteriorating structure was transformed into a multilevel family residence. The project reorganizes the original two-story interior by introducing a mezzanine and seven interconnected spatial levels, addressing the requirements of a multigenerational household within a limited footprint. The design prioritizes individual functional spaces rather than mechanically transformable elements, using an L-shaped staircase to establish circulation and spatial variation. Skylights, carefully positioned windows, a red maple-leaf wall, and a vertical garden create connections between interior and exterior environments. The renovation also preserves the tower’s established exterior profile in accordance with local regulations, while allowing greater architectural freedom within concealed areas. A silver roof distinguishes the completed building from the surrounding red rooftops, reflecting an approach that combines domestic adaptation with sensitivity to the existing urban fabric.

House on the House by Wutopia Lab explores how a compact residential interior can accommodate complex domestic requirements through spatial organization and functional diversity. Lead architect Yu Ting approached the renovation as a system of interconnected spaces, each designed to address particular activities and personal needs. Rather than adopting a “Transformers”-inspired strategy of mechanically adaptable elements, the design favors individual components with clearly defined purposes, creating variety through their relationships within the house.

The residence occupies the upper portion of a former water tower at Number 23, Lane 389, East Jinling Road, in an older Shanghai neighborhood. Originally built for water storage, the narrow tower has elevations measuring no more than four meters in width. Following the Cultural Revolution, it was converted into residential accommodation, with eight columns supporting a southward extension above a passage used by neighborhood residents. The structure eventually accommodated four households on separate floors. Before renovation, the apartment comprised two floors connected by a ladder occupying part of the kitchen, and years of deterioration had left it in poor condition.

The existing residents were grandparents and their granddaughter, who hoped the renovated home could also accommodate their son and daughter-in-law. To address the household’s needs, the architects developed a program containing more than 140 requirements, informed by interviews with the occupants. This detailed understanding of daily routines guided the interior arrangement, with emphasis on comfort, privacy, and the efficient distribution of essential domestic functions.

The introduction of a mezzanine transformed the original two-story configuration into a series of split levels. Although dividing the available volume reduced the dimensions of individual spaces, it also established greater functional independence and privacy. The architect described this spatial strategy as “Squeeze”, using the division of space to create distinct rooms rather than a continuous, undifferentiated interior. An L-shaped staircase connects seven levels, extending the experience of movement through the compact residence.

Beyond separating functions, the architects sought to create a sense of “journey” between rooms. The circulation sequence introduces changes in height, enclosure, and visual connection, suggesting movement through a collection of small houses rather than a single confined dwelling. A corridor featuring a red maple-leaf wall, together with a skylight, an aquarium, and a bay window associated with the children’s room, contributes to this impression of an exterior passage within the residence.

The relationship between indoor and outdoor environments is reinforced by the tower’s elevated position. Windows frame views of the surrounding neighborhood, visually extending the interior beyond its physical boundaries. Carefully positioned skylights introduce daylight, while painted walls in the children’s room establish a distinct atmosphere. These elements create varied spatial experiences without requiring an increase in floor area.

The family initially requested a garden on the sloping roof, but concerns about safety and future conditions led the architects to introduce a vertical garden within the balcony instead. This planted space creates an intermediate environment between the enclosed rooms and the exterior, contributing to the project’s exploration of flexible boundaries between domestic and outdoor spaces.

The renovation was also shaped by restrictions on modifications to the building’s exterior. Following guidance from the local administrative authorities, Wutopia Lab retained the tower’s existing external profile. The architects repaired the exterior walls, patio, and roof, reorganized the drainage system, and repainted the structure together with the residential spaces below. These interventions improved the building’s condition while maintaining its established form within the neighborhood.

Greater design flexibility was possible in areas not directly visible from outside. The internal elevation of the patio and the attic facade were redesigned behind the preserved exterior surfaces, allowing the architects to introduce a different architectural expression within the existing envelope. Although the external appearance and interior spaces follow contrasting visual approaches, both respond to the tower’s irregular structure and accumulated modifications.

The project also considers the relationship between the renovated apartment and the other households occupying the former water tower. By limiting visible interventions, the architects maintained the building’s familiar presence within the residential community. The repaired exterior contributes to the surrounding streetscape, while the substantial reorganization of the interior remains largely concealed from neighboring residents.

The roof provides the renovation’s most prominent architectural expression. Its silver surface stands out against the surrounding red rooftops, producing a distinctive composition when viewed from above. The contrast establishes the tower as both a vantage point overlooking the neighborhood and an architectural element within the wider urban landscape.

House on the House demonstrates how the reorganization of a restricted interior can support varied domestic activities while respecting the constraints of an existing structure. Through split-level spaces, differentiated circulation, and carefully considered connections between inside and outside, Wutopia Lab transforms a deteriorating former water tower into a family residence without substantially altering its relationship with the surrounding neighborhood.