18 House is located in a quiet dead-end alley in Ho Chi Minh City, Vietnam. It belongs to a young couple with a child. The compact 18-square-meter plot posed a challenge: creating a high-quality living space within such a limited footprint. This constraint was also the project's only design brief at the outset. Our approach, therefore, sought to balance maximizing space with embracing the creative freedom we were given.

Given the height restriction, we aimed to achieve more than just three floors. Instead of a conventional vertical circulation core, we designed a staircase along the periphery, utilizing the space beneath it for storage cabinets, toilets, and bathrooms. This layout also created a spacious vertical void, which could accommodate a bunk bed or a reading loft.

To maintain an open and airy atmosphere, we kept the stair balustrade as minimal as possible. For child safety, rope nets can be added in the future when the child starts learning to walk. Despite the space constraints, we prioritized integrating greenery to soften the dense urban surroundings. A shared plant bed connects the master bedroom with the reading loft, while the rooftop serves as a mini vegetable garden.

The exterior design revolves around the concept of porosity. The façade facing the alley features a system of adjustable slits of varying heights, allowing users to control ventilation by selecting specific openings. These slits make up approximately 50% of the washed-terrazzo façade. Beyond enabling airflow, they ensure privacy while allowing ample daylight inside. To mitigate heat gain from the eastern sun between 9 AM and 11 AM, the bedroom’s exterior wall was thickened and sculpted with a triangular profile, deflecting sunlight and preventing overheating during Ho Chi Minh City's hot season.

We also designed the house with adaptability in mind. In the future, a loft can be added above the parking area on the ground floor, taking advantage of the double-height entry space. Through various space-maximizing strategies, we hope the house will continue to reveal new possibilities for its occupants over time. More importantly, we believe that architecture, regardless of plot size, should serve the higher purpose of enhancing everyday life.

Principal architects: Phan Khắc Tùng, Huỳnh Anh Tuấn

Photography: Hiroyuki Oki, Thiết Vũ