ABC Flats by Isso Architects

ABC Flats is a co-housing project strategically located in the densely built Cilandak neighborhood of South Jakarta. Occupying a modest 175m² plot with a total built area of 423m², this three-story building exemplifies the fusion of functional efficiency with architectural fluidity, redefining urban co-living within a tight footprint. Designed to accommodate 11 rooms with ensuite bathrooms, ABC Flats offers a flexible and communal residential model, complemented by a rooftop pantry and shared area for residents, fostering interaction and shared experiences.

Context and Urban Approach

Set amidst a compact urban fabric of conventional residential buildings, ABC Flats presents a striking yet harmonious contrast through its curvilinear forms and thoughtful spatial design. By embracing soft, bending geometries, Isso Architects have introduced a language of subtle fluidity to the project, differentiating it from the rigid orthogonal structures of the surrounding streetscape. Cylindrical elements are repeated throughout the composition, creating a visual rhythm that enhances both the building’s identity and functional efficiency.

Architectural Form and Façade

The exterior of ABC Flats is characterized by its raw concrete surfaces, sculpted with gentle curves and bends that introduce playful visual dynamics while maintaining structural clarity. Cylindrical and curvilinear elements punctuate the façade, offering a rhythmic cadence that guides the eye upward and reinforces the building’s cohesive volumetric language. The façade not only communicates movement and softness but also strategically frames views and daylight penetration, ensuring that each interior space benefits from natural light and a sense of openness.

Interior Design and Spatial Experience

Entering ABC Flats, visitors are welcomed by a triple-height central staircase with solid wooden flooring beneath, illuminated by a skylight that filters natural light into the heart of the building. This central atrium is accentuated by a long reflective pond, which amplifies the interplay of light, air, and water, creating an ever-changing visual experience reminiscent of a slowly turning kaleidoscope. The architects describe this phenomenon as a dynamic composition where spatial perception subtly shifts by the hour, adding an element of temporal interaction to the built environment.

The interiors feature curved walls and sculptural forms that echo the fluidity of the façade, enhancing the sense of movement and softening the compact volume of the building. Sections of railing walls are strategically detached, allowing light and shadows to dance across surfaces, creating a sense of openness and visual connectivity between floors and spaces. Wood finishes, clean lines, and a neutral palette complement the raw concrete surfaces, establishing a balance between solidity and permeability throughout the interiors.

Layout and Functionality

ABC Flats is organized into three longitudinal zones: stairs, aisles, and rooms. This linear arrangement simplifies circulation while optimizing space efficiency. All mechanical and electrical systems are consolidated within a central shaft, ensuring ease of maintenance and minimizing clutter within living areas. Despite the compact size of the building, the spatial hierarchy and careful detailing create a sense of expansiveness and comfort, highlighting how thoughtful design can maximize usability within limited urban plots.

The rooftop area serves as a communal hub, featuring a small pantry and shared space for residents. This extension beyond private rooms encourages interaction, social engagement, and informal community-building, a key objective of co-housing design. The combination of private and shared spaces allows residents to enjoy both solitude and connection, embodying a flexible urban lifestyle.

Materiality and Finishing

Material choices reinforce the project’s architectural narrative. Raw concrete, left exposed, defines the structural and aesthetic language of the exterior, while wood and neutral finishes warm the interiors and enhance the sensory experience. The juxtaposition of solid and soft materials reinforces the dialogue between permanence and fluidity, making ABC Flats a visually compelling and livable urban residence.

Conclusion

ABC Flats exemplifies how compact co-living architecture can combine functional efficiency, spatial fluidity, and aesthetic innovation. By merging curvilinear forms, thoughtful materiality, and a dynamic interplay of light, air, and water, Isso Architects have created a building that is both visually distinctive and highly functional, offering a refreshing reinterpretation of urban co-housing in South Jakarta.

Photography: Ernest Theofilus