Winners and Finalists
The New Generation of Yaodong Cave Dwellings, Loess Plateau
Aims and Objectives
Located in north central China, the Loess plateau of undulating hills covers nearly 500,000 km2. Forty million people live in this region, 75 per cent of whom are farmers in rural areas. Living conditions are amongst the lowest in China, although some incomes are now increasing and there is a widening income range. Ninety per cent of the rural population live in various types of yaodong, or cave dwellings. The earliest types of these were dug into the hillsides and they have since evolved into masonry dwellings that are more disengaged from the mountainside (only 10 per cent are still in the dug-out form, 70 per cent have their rear wall abutting the mountainside and the remainder are entirely freestanding). One family dwelling usually consists of two or three arched openings and the units are interconnected inside. The spaces between the arched shapes are filled with earth to make a thick flat roof. The free-standing yaodong dwellings differ from ordinary free-standing houses in that traditional designs and simple materials are used as well as a traditional cluster configuration, to maintain a strong sense of community.
Environmental SustainabilityThe design involves using the local topography to provide the housing structure, thereby reducing the need for roofing and wall construction materials. The building materials used are sourced locally and recycled building materials have been used wherever possible.
The use of solar spaces helps to reduce the need for internal heating. The earth sheltering nature of the design means that even at external temperatures of -20°C, the internal temperature can be maintained at 10°C, with only the use of a traditional kang (stone bed linked to an internal stove).
Old style Yaodong dwellings consume 15 kg of coal per m2 for heating; concrete houses require 25 kg, whilst new yaodong dwellings require 0-5 kg. With a CO2 emission ratio for local coal at 2.4:1 the CO2 emission saving per property is 2,400 kg (2.4 tonnes) for a 100 m2 dwelling. The project has resulted in CO2 savings and minimisation of pollution from the construction process through the use of existing terrain and minimal construction materials.
The houses are cut into hill terraces on land that is infertile or hard to farm, thus maintaining the amount of land available for agriculture.
Financial SustainabilitySince there is no government support and the housing costs are funded by the families living in the houses, the project does not rely on an external source of funding. The costs of GBRC technical support are met by a national government subsidy which will be continuing.
Retaining young people in the area with more modern housing helps boost the local economy and prevents the downward spiral associated with rural depopulation.
The cave dwelling homes of the area have been promoted as a tourist attraction (due to historical connections with the early days of Mao-Tse-Tung). The world’s largest cave dwelling complex (in the north of Yan’an city) has been converted into an eight-storey hotel with 300 rooms. Some retain the traditional heated stone bed; others have ordinary beds to meet the demands of tourists.
The costs of the new yaodong dwellings are approximately half of that of the new flats being built using western methods and materials in the nearby towns and this helps to encourage local young people to stay in the rural area.
Utility bills are lower since the new design provides greater warmth in the dwelling through the use of the sunspace at the front of the dwelling.
Social SustainabilityPeople work together with their friends and neighbours to build their own homes. The design of the housing is more conducive to people meeting their neighbours than living in one of the new flats in the local towns. Construction skills and knowledge of energy saving have both increased as a result of the project and the retention of local young people helps to maintain the community infrastructure.
A healthier living environment in the houses has bee created due to the improved ventilation and a reduction in the damp levels through enhanced heating.
Participation in the design process is very innovative in this context, and has been particularly valuable because the GBRC clearly attach high importance to the comments of the residents.
BarriersBoth the traditional understandings and new aspirations needed to be challenge. Young people want a modern city-type dwelling as the desire to match western residential standards is pervasive; older people prefer the old-style dwellings and don’t want to change and the local government wants any modernisation to look like London, Shanghai or Beijing.
Lessons LearnedResidents need to be advised on how to take greatest advantage of the new dwellings and demonstration houses are important in winning over local residents to new design ideas. An entirely local design process is impossible because residents equate modern, non-local building materials with progress and an increase in status.
Ecological principles need to be applied differently in urban and rural areas since there is greater emphasis in the rural areas on retaining some of the traditional design values. High tech solutions and expensive methods are not appropriate in these rural areas. Promoting low-tech solutions will not win local residents over unless there is a significant increase in living conditions. In this case this was achieved with an increase in the air quality in the dwelling.
EvaluationMonitoring has been carried out on the 85 dwellings built as part of the pilot study. This looked at the thermal performance and occupants’ satisfaction. Residents were closely involved in the monitoring process. It was found that indoor temperatures are higher on average by five degrees in the new buildings (i.e. increasing from 10 to 15 degrees at midday) and indoor daylight levels and ventilation are much improved in the new buildings.
TransferStarting with a pilot project of 85 houses in Zaoyuan village (1996-2001), the project has now seen the development of over 1,000 dwellings by local families using self-help construction methods in both rural and suburban areas.
Variations on the design have also been used by a local real-estate company and a further 1,200 dwellings have been developed using the new designs, as well as two large hotels. A new yaodong dwelling community has been established in the eastern suburb of Yan’an city and a second one is under construction. Several private entrepreneurs have plans to develop in the Loess Plateau (Gansu and Shaanxi provinces).
Academics and architects from other parts of China have visited the project and developed similar projects to improve vernacular architecture and make it more energy efficient. For example, Professor Jiang Shuguang from Shi He Zi University in Xinjiang Province is developing a new kind of dwelling for rural people. What is common in these efforts is the idea that new forms can be developed that can carry the traditional values of a local community; that this is a part of what it means to be ‘sustainable’.
Professor Liu Zheng from Polytechnic University of Inter-Mongolia is developing a new kind of improved vernacular (tented) dwelling for the Mongolian rural population.
Professor Liu Jiaping
Research Centre of Green Building
Xi'an University of Architecture and Technology
Yanta Road 13, Xi'an
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