Rooftop House in Beijing, China by BWAO

Article source: BWAO

Client is a tech company that occupies an entire office building. The office building rooftop has great corner views, either to the city or to the mountains in the background. A rooftop house is built to take advantage of this as well as providing a home like space for staff members.

The building massing is adjusted in a fashion that corresponds to the views in the background, Image Courtesy © BWAO

• Architects: BWAO
• Project: Rooftop House
• Location: Beijing, China
• Team: Bao Wei, Jia Yan, Chen Minglei, Li Shan, Huang Tanyu
• Structural Engineer: Sang Yangyong
• MEP Engineer: Hang Yunfeng, Tang Chengwu, Wei Deliao
• Lighting Consultant: Zhou Xuanyu
• Contractor: Beijing JHYHS Construction
• Main Products: DBS aluminum alloy windows and doors system, Dupont exterior wall paint
• Building Area: 180 sm
• Design Period: 04/2018 – 08/2018
• Construction Period: 08/2018 – 08/2019

Southwest Corner, Image Courtesy © BWAO

Existing Conditions

The site is on the rooftop of a five-story office building with a dimension of 33mx25m in plan. Surrounded by a 1.2 meter high parapet at the periphery, the only built structures on top is a T shaped shed that houses staircase and elevator equipment, and a series of air vents that puncture through the floor slab.

Design Strategy

To maximize the building volume and to be unnoticeable from the street level, the building mass is offset from the parapet boundary. The outer limit of the building is shaped by this restriction and locations of existing air vents.

In order to have an unobstructed view over the parapet, the entire building mass is elevated for one meter, gaining a vantage point out to the open for all activities happening inside.

Air vents coming out of the exisiting building rooftop set the limit for the house, Image Courtesy © BWAO

North window, Image Courtesy © BWAO

The new building plan matches the T shaped shed with a U configuration. The western portion houses programs such as kitchen, dining, bar and lounge. The eastern portion has a tea house and a living room, relatively private in terms of usage. The middle portion is comprised of service programs such as a mechanical room and a bathroom.

Four distinctive windows are placed at four corners to provide different viewing experiences to the outside sceneries. Three courtyards are introduced as to create inner views as well: a tree yard to the west, a water yard to the East, and a sun yard in the middle. These courtyards bring natural elements such as light and shadow further into the house.

Structural Strategy

In order to elevate the building for one meter, a new datum is established on the existing roof structure. This new floor structure is anchored to the main beams and columns at the floor below, allowing the house structures to grow freely on this new platform.

Tree courtyard brings a piece of green to the zen like garden, Image Courtesy © BWAO

Water courtyard uses the elevated depth to creat a fish pond, Image Courtesy © BWAO

The cavity space in-between the new floor plate and existing roof not only helps with the thermal performance of the new house, but also provide depth for earth and water features of the courtyards and space for air vents that feed into the rooms.

Building Material

The main building structure is steel, with CMU blocks as wall infill. Insulation foam panels are applied to the exterior with plaster and paint as final finish. Interior is furnished with wood floor and plastered ceiling and walls. Due to a tight budget, the visual interests are focused on views into the courtyards and out to the landscape, rather than on exquisite materials.

Sky courtyard brings the light and shadow into the terrace space, Image Courtesy © BWAO

Northwest corner window looking out to the landscape faraway, Image Courtesy © BWAO

Southeast corner window looking out to the city, Image Courtesy © BWAO

Corner Window view to the city, Image Courtesy © BWAO

Northeast strip window looking out to the mountain in the background, Image Courtesy © BWAO

Bar opening at a higher elevation as seen from the kitchen below, Image Courtesy © BWAO

Bar with view to tree courtyard, Image Courtesy © BWAO

Kitchen area with all the furnitures integrated into a zigzag configuration, Image Courtesy © BWAO

Kitchen working area, Image Courtesy © BWAO

Living room area with sunken space to hold cosy sofa seatings, Image Courtesy © BWAO

Teahouse with view to living room, Image Courtesy © BWAO

Axon view to illustrate how the house sits on top of the existing building, Image Courtesy © BWAO

House Site Plan, Image Courtesy © BWAO

House Plan, Image Courtesy © BWAO

Tags: Beijing, China

Categories: Building, House, Residential

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