A narrow atrium brings daylight into windowless rooms on four storeys at this renovated house in Hanoi by Vietnamese office AHL Architects Associates.

The existing building was a typical Vietnamese "tube house", with a long, thin plan and few windows. AHL Architects Associates was tasked with reorganising the plan to make better use of space and to increase natural light and ventilation.

The architects began by relocating the staircase from the centre of the house to along one wall, then added a large skylight overhead. They also removed sections of the floor, creating the four-storey atrium and a series of indoor balconies.

"The staircase and corridors were designed not as a simple and boring path but as a continuous and sequential space which becomes a living space," explain the architects.

The wall running alongside the atrium is lined with white ceramic tiles, giving it a ridged texture, and all of the balustrades are glazed to let more light through.

Just in front of the staircase, the entrance to the house is set within a recessed driveway at the end of a ramped platform. Once inside, residents can walk through to a kitchen on the ground floor or head upstairs to a double-height living room on the floor above.

Bedrooms are located on the first, second and third floors, and the top storey also features a dedicated worship room and a roof terrace.

Another "tube house" we've previously featured on Dezeen is the four-storey Stacking Green house, which features a a vertical garden on its facade. See more Vietnamese architecture on Dezeen.

Photography is by Anh Duc Le.

Here's more from AHL Architects Associates:

4.5x20 House

This house was designed for a young family with one child and grandmother, located in Van Phu, a new urban area in Hanoi, Vietnam. The existing design is boring (like thousands of other houses in Vietnam): lost of natural lighting and ventilation; simple space with core (staircase and toilet) in the middle and two bedrooms at two sides. Client (young family) needs something different from the existing. They need their own house, their style. This situation requires a smart solution for traffic, thereby creating interesting solutions of space, daylight and natural ventilation.

Based on their requirements, the program is quite simple: garage (for 2 cars), kitchen on the 1st floor, bedroom (for grand mother) and living room on the 2nd floor, master bedrooms on the 3rd floor, small guest room, sky terrace and worship on the 4th floor... but they need the architects focus on the creation of public spaces.

With a simple strategy "traffic creates space and function", we started by changing the location of staircase. Unique and continuous spaces were proposed based on the new staircase. The staircase and corridors were designed not as a simple and boring path but as a continuous and sequential space which becomes a living space.

Along with identifying new locations for staircase, the voids are also determined for natural lighting and ventilation. An atrium in the middle of house was created to bring daylight to lobbies and all rooms without window to outside. In addition, that allows full connection between the four levels of the house vertically.

The central space is the biggest volume where a double height living room locates, is surrounded by opening staircase, autrium and big windows.

The restrained and limited material palette of white painted ceramic tiles, wood, and glass avoids unnecessary ornamentation in order movement through a variety of opening spaces.

Type of development: Renovation of typical tube-house
Dimension: 4.5x20
Location: Van Phu New Urban Area, Hanoi, Vietnam
Status: Finished
Cost: 112,000 usd
Date: 2012

Architects: AHL architects associates
Architects in charge: Hung Dao, Tuan Anh Mai, Son Chu, Hieu Hoang, Nghia Mai, Tung Nguyen, Truc Anh Nguyen