Urbanization across Southeast Asia is transforming rural landscapes at an accelerating pace. In Vietnam, city-style tube houses have begun appearing more and more densely in village areas, disrupting the longstanding visual and spatial character of rural communities. The Dien Khanh house, designed by 6717 Studio, offers a different model: one that retains the traditional familiarity of rural housing while satisfying the requirements of contemporary life. The project demonstrates how creating a fresh living environment connected to nature does not mean abandoning modern comfort. By studying how passive house architecture creates healthier buildings, architects working in tropical climates can apply similar principles of natural ventilation and material honesty to designs that feel rooted in place.
The Atrium as a Central Organizing Element in Home Design
The Dien Khanh house uses an atrium and skylight as the spatial and environmental heart of the home. The living and relaxing spaces are divided by this central void, which pulls natural light and wind deep into the building. The parents’ bedroom sits on one side of the atrium, separated from the living room and kitchen by a small garden planted within the void. This garden introduces vegetation, soil moisture, and visual greenery directly into the center of the floor plan. The arrangement allows all primary rooms to face the interior garden rather than the street, creating privacy without solid barriers.
The atrium serves three distinct functions simultaneously. It acts as a light well, bringing daylight into rooms that would otherwise rely on electric lighting for most of the day. It functions as a ventilation stack, drawing hot air upward and out through the skylight while pulling cooler air in from shaded openings at ground level. And it provides acoustic separation between family members in different rooms without requiring full-height walls. This type of passive house retrofit approach can be adapted to existing townhouses in dense urban areas, using the existing roof structure to create a lightwell where none existed before.
Sizing an Atrium for Effective Natural Ventilation
The effectiveness of an atrium for natural ventilation depends on its proportions. Research on atrium performance in tropical climates shows that the following ratios produce reliable airflow:
| Atrium Aspect Ratio (Height:Width) | Air Change Rate (ACH, tropical summer) | Daylight Penetration Depth | Typical Floor Area Served |
|---|---|---|---|
| 1:1 | 2 – 4 | Partial (top floor only) | 50 – 80 m² |
| 1.5:1 | 4 – 8 | Good (top and middle) | 80 – 130 m² |
| 2:1 | 6 – 12 | Full (all floors) | 100 – 200 m² |
| 3:1 | 8 – 15 | Full (all floors) | 150 – 300 m² |
The Dien Khanh house achieves a ratio close to 1.5:1, which balances effective stack ventilation with manageable floor area. The skylight at the top of the atrium is oriented to capture prevailing winds while allowing hot air to escape through adjustable louvers.
Daylight Design and Natural Ventilation Through Layered Openings
Natural light and wind enter the Dien Khanh house through a carefully sequenced set of openings rather than a single large window. The skylight above the atrium provides the primary daylight source. Secondary windows at the perimeter of each room allow cross-ventilation when winds blow from the side. The combination creates predictable air movement throughout the day, even on days with minimal wind. Unlike mechanical air conditioning, this system requires no energy input and produces no heat waste. Workshop projects focused on natural ventilation often explore similar principles at the residential scale, applying the same physics to different building types.
Window Placement Strategies for Cross-Ventilation
- Opposite wall placement: Windows on two facing walls create direct cross-flow. Optimal when both openings are at least 30 percent of the wall area.
- Offset placement: Windows on adjacent walls generate a swirling pattern that reaches more of the room volume. Useful in deep rooms where direct cross-flow would only sweep the perimeter.
- High-low pairing: A high outlet (clerestory or skylight) combined with a low inlet creates stack-driven airflow that works even when wind is still. This is the strategy used in the Dien Khanh atrium.
- Operable transoms above doors: Small openings above internal doors allow air to move between rooms even when privacy demands closed doors.
The Dien Khanh house uses high-low pairing as its primary strategy, supplemented by offset window placement in the bedrooms to circulate air through the sleeping areas. The result is a building that stays cool and ventilated without fans or air conditioning for most of the year.
Material Choices That Honor Traditional Craft
Finishing materials in the Dien Khanh house were chosen for their cultural familiarity as much as their technical performance. Terrazzo is used throughout as a material that previous generations of Vietnamese builders relied on. It handles the disadvantages of the local soil conditions, resists moisture, and stays cool underfoot in hot weather. The stair and building finishes use terrazzo in a contemporary application that connects the new house to the craft traditions of the region. White paint and light wood finishes create spacious and bright interiors while keeping the construction within a realistic budget. These small studio architecture strategies for material selection prioritize what is available locally over what is imported or exotic, a principle that keeps costs predictable and supply chains short.
Why Terrazzo Works in Tropical Climates
Terrazzo has properties that align well with the demands of tropical housing. The cementitious base absorbs and releases moisture, buffering indoor humidity swings. The stone aggregate chips provide thermal mass that stays several degrees cooler than ceramic or porcelain tile under direct sunlight. And the surface can be polished smooth enough to discourage mold growth while remaining porous enough to breathe. The material also wears well under barefoot traffic, which is common in Vietnamese households. Proper sealing cycles every 3 to 5 years maintain the surface without the need for replacement.
Curved Stair Design as a Spatial Solution for Irregular Sites
The stair in the Dien Khanh house is the architectural highlight of the project, and it solves a specific site problem. The property has a broken corner an irregular angle that makes a standard rectangular stair layout awkward. The curved stair, combined with the atrium at this broken corner, creates a sense of fluid motion and visually breaks the awkward geometry. The curve also softens the transition between the living spaces on the ground floor and the bedrooms above, making the vertical circulation feel like part of the living area rather than a separate circulation core.
Curved stairs introduce specific structural and construction considerations. The stringer must be fabricated from bent steel plate or laminated timber, both of which require skilled labor. The tread depths change along the curve, which means each tread must be individually templated and cut. In the Dien Khanh house, terrazzo is used for the stair finish, which allows the treads to be cast in place against the curved formwork. This approach to custom fabrication shares principles with sound studio construction, where irregular geometry and site-specific solutions are the norm rather than the exception.
Structural Options for Curved Stairs
| Construction Method | Minimum Radius | Relative Cost Factor | Typical Span | Suitable Finish |
|---|---|---|---|---|
| Steel stringer + timber treads | 1.5 m | 1.0 (baseline) | 3 – 5 m | Wood or carpet |
| Reinforced concrete cast in place | 2.0 m | 1.3 – 1.5 | 3 – 6 m | Terrazzo, tile, or stone |
| Glulam timber stringer | 2.5 m | 1.5 – 2.0 | 3 – 5 m | Clear finish wood |
| Precast concrete segments | 3.0 m | 1.2 – 1.4 | 3 – 4 m | Terrazzo or stone |
The Dien Khanh house uses cast-in-place concrete with a terrazzo finish, which provides the structural rigidity needed for the curve while keeping the material palette consistent with the rest of the house.
Traditional Furniture and Interior Elements in a Contemporary Home
Traditional elements are incorporated into the Dien Khanh interior in specific, curated ways. The living room includes a wooden sofa of the type commonly found in traditional Vietnamese housing spaces. The patio seat by the atrium garden references the outdoor seating areas that have been part of local domestic architecture for generations. These pieces coexist with modern furnishings and clean white walls. The effect is not a reproduction of a traditional interior but a layering of old and new that gives each element more meaning than either would have alone. When designing efficient guest houses and small dwellings, the same principle applies: a few carefully chosen traditional elements give character to a compact space without overwhelming it.
The white paint and light wood that define the interior surfaces serve a practical purpose beyond aesthetics. In a tropical climate where sunlight is intense, white walls reflect light deep into the interior, reducing the need for artificial lighting during daytime hours. Light wood floors and furniture do not absorb as much heat as dark finishes, keeping surface temperatures lower. The combination means the interior stays visually bright and thermally comfortable without active cooling. Working with a dedicated design studio that understands these principles is the most reliable way to adapt them to a specific site and budget, whether the project is a full house or a single room.