3fconcept Moves the Stair onto the Facade of a Compact Family House in Hue

Small urban houses in Vietnam tend to solve the same problem the same way: a narrow plot, a deep floor plan, and a light well punched through the middle to bring in daylight and air. Lily Block Residence by 3fconcept, completed in 2026 on a 102 m² plot in western Hue, questions that habit directly. The house fits 184 m² of family life onto the site, and it does so without the central void that most of its neighbours would rely on.

The move worth your attention is simple to describe: the vertical circulation core leaves the interior and moves to the main facade. The architects argue that tropical atriums bring solar heat gain and rainy-season leaks as often as they bring relief, so they replaced the void with a stair, a continuous vertical volume and a stack-effect strategy. The result is a white, block-built house that sits back and lets light, shadow and planting do the expressive work. In a city as loaded with history as Hue, that restraint feels like a position, not a lack of ideas.

Gate, Court and Stacked Volumes

From the street you read the house as a set of white volumes stacked above a lawn and a gravel court, screened by a perforated metal gate. A tree grows on the roof. Nothing here imitates the imperial city's tiled roofs or carved timber, and the architects say outright that they wanted to avoid pastiche.

We think the gate is the quiet hero of the front. Perforated panels filter views and breeze without sealing the court, so the garden reads as a semi-public threshold rather than a fenced-off yard. At blue hour, the glow behind the screen tells you the ground floor is open to that court, not walled away from it.

Circulation on the Facade

The concrete stair with its floating treads rises behind a glass wall, above a sloped grass bank and beside the paved drive. Putting circulation at the front turns the most mundane element of a house into its public face. It also does climatic work: the stair occupies the sunniest edge, so it takes on heat and glare that would otherwise fall on the rooms.

The cat on the landing is a useful reminder of scale. These treads are not a ceremonial staircase; they are the everyday route between floors, open to the lawn and to dappled sun. Daily movement becomes a walk along the garden edge, which is a generous thing to offer a family on a plot this tight.

Blocks, Slots and Shadow

The project name makes sense once you see the details. Concrete blocks push through slim window slots in the white wall, and cantilevered concrete balconies project from the volume. Against the stucco, tree branches throw shifting shadows, and the wall becomes a screen that records the time of day.

This is where the 'minimalist backdrop' idea pays off. The palette is concrete, glass and white render, and the facade relies on depth: recesses, projections and slots. The pieces read as objects lodged in a wall rather than as decoration applied to it.

A Ground Floor That Belongs to the Garden

The ground floor opens through sliding glass to a gravel court with wire chairs, a multi-stemmed tree and large-leaf plants. An outdoor washbasin sits on one side of a concrete wall, and a reading nook among tropical foliage sits on the other. The living room looks out to a block-walled garden, so even the television wall has greenery in its peripheral view.

The planting is part of the climate strategy, not just a soft edge. The architects describe the ground-level vegetation and concrete steps as the first stage of air intake, filtering and cooling air before it enters the house. On a plot of this size, giving that much of the footprint back to green space is a real trade-off, and we think it is the right one.

Kitchen, Living and Raw Concrete

Inside, the language shifts from white to grey and black. A raw concrete wall runs beside the living room's large window, black timber cabinetry anchors the kitchen, and a long dining table sits under pendant lamps with the garden beyond. A red cat painting on the concrete brings a bit of humour into an otherwise sober room.

Living, kitchen and dining form one continuous ground floor, which supports the idea of programmatic compression. Instead of separate rooms competing for scarce square metres, the family gets one shared space that borrows depth from the garden on either side.

Light Down the Spiral

Alongside the facade stair, a white spiral staircase with a slim steel balustrade links the floors inside. Looking up the stairwell, you see a skylight slot, a plant set in front of a painting and a round paper lantern. The light well has not disappeared; it has shrunk to the width of a stair and moved to where it can do its job without becoming a liability.

That is the more nuanced reading of the project. 3fconcept did not reject vertical voids outright. It sized one precisely, tied it to circulation and used it as the chimney for the stack effect, rather than leaving an open atrium that collects rain and heat.

Looking Out to the Hills

From a distance, the house sits among forested hills with a conical peak behind it, a reminder that western Hue sits close to rising ground. Upstairs, a bedroom opens through a wide horizontal window and sliding door onto a balcony above the treetops, and a study desk sits under a long window framing a green slope.

The horizontal windows are carefully judged. They frame the landscape as a band, keep out the high sun, and give the private floors a calm, distant outlook that contrasts with the busier ground floor.

Edges, Roof and Evening

At the top, a concrete planter and water edge catch olive branch shadows across the white wall, and a concrete balcony with a steel railing looks west toward sunset over the utility poles of the neighbourhood. The roof is where the house finishes its argument: a garden, a home office and a worship room share the top floor, giving the family's spiritual and working life the best air and light in the building.

Plans and Drawings

The site plan maps sun path arcs and wind directions alongside fields, a lake and two nearby tombs, which is a candid acknowledgement of the house's real context on Hue's edge. The ground floor groups porch, mudroom, bathroom, laundry, living area and kitchen with dining, all ringed by planted borders. The first floor holds a master bedroom, two further bedrooms and two bathrooms around the spiral stair.

The rooftop plan places the home office and worship room beside the stair, with a planted garden and a tree taking up the rest. The exploded axonometric makes the stacking legible: garden at the base, sleeping in the middle, terrace on top.

The ventilation diagram is the most persuasive drawing in the set. Blue arrows show cool air entering low through planting and steps, and red arrows show warm air rising through the stair to roof openings. The structural axonometric highlights a concrete frame of columns and beams inside the outline, which explains how the blocks and cantilevers can sit so freely on the facade.

Why This Project Matters

Lily Block challenges a typological reflex that many Vietnamese architects treat as settled. The central light well has become shorthand for climate-responsive tube houses, but here the architects point out what it costs in heat and leaks, and offer an alternative: move the circulation to the facade, keep one tight vertical shaft and let stack ventilation do the rest. Whether every claim holds across Hue's monsoon seasons is something only years of occupation will prove, but the reasoning is clear and testable.

It also offers a useful answer to building in a historic city. Rather than borrowing ornament from Hue's past, the house earns its place through planting, shade and attention to the hills and fields around it. For anyone designing small family homes on constrained tropical plots, the lesson is that you can treat the facade as working infrastructure and still have it look calm.

Lily Block Residence by 3fconcept, Hue, Vietnam. Area: 184 m². Completed: 2026. Photography: Nguyen Dang Hieu.

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