When concrete was considered sustainable: ecological crisis, technological transition and the prefabricated concrete rural houses in Jiangsu Province from 1961 to the 1980s

Abstract

This paper explores the creation, development, and dissemination of prefabricated concrete rural houses in Jiangsu Province in East China from 1961 to the 1980s, an example of the technological transition provoked by the depletion of forest and timber in China. Through archival research, fieldwork and interviews, the paper examines the two waves of design and dissemination of prefabricated concrete rural houses between 1961 and 1965 and their subsequent ‘vernacularisation’ in the 1970s and the 1980s. This research provides a twofold insight into the current scholarly debates surrounding built heritage and global climate change. On one hand, it addresses a historical context of concrete overuse in contemporary China, a matter of critical importance in relation to carbon emissions and global climate change. On the other hand, it offers a counter-argument to today's call for reintroducing timber structures in many places, as evidenced by the case of East China, where the widespread use of materials like concrete was primarily a consequence of the ecological crisis following decades of deforestation and timber resource depletion. In addition, the ‘vernacularisation’ of concrete structures manifested by this case still provides lessons for today’s efforts to popularise more eco-friendly construction materials and technologies, especially in rural areas, and the prefabricated concrete houses possess potential heritage values as trackers of ecological changes.

1 Introduction

With the global climate emergency, timber is increasingly revived as a more environmentally friendly and carbon–neutral substitute for current construction materials, especially steel and reinforced concrete (Campbell 2019, 141; Zaman et al. 2022). In the Chinese context, due to the long tradition of building in timber, timber architecture is also being promoted with a cultural rhetoric of reviving the Chinese building tradition (Li et al. 2019). However, this research seeks to answer one critical question: Why was this building tradition in timber discontinued in the first place? It turns out that, by the early 1960s, the problem of deforestation and depletion of timber had become so severe that vernacular architectural tradition in timber had to be abandoned, at least in East China, and prefabricated concrete was promoted as a more ‘sustainable’ alternative. Today, it certainly seems counterintuitive that, only six decades before, timber was identified as an ‘unsustainable’ building material and should be replaced by reinforced concrete. Such a historical fact not only calls for a more rigorous examination of the overall environmental impact of timber architecture but also invites further exploration of the relationship between modern architecture and our current climate and environmental crisis.

The environmental rhetoric for promoting timber buildings is based on the argument that they are ‘identified as having the dual benefit of both reducing embodied emissions and also locking up carbon dioxide during their use until end of life’, thus greatly reducing the carbon footprint of the construction industry (Campbell 2019, 146). However, counter-arguments for exploiting timber for building activities, especially in the Chinese context, are abundant, even if one is only skimming through the academic publications throughout the 20th and 21st centuries. As early as 1918, Ling Daoyang (D. Y. Lin), one of the founding fathers of forestry in China, wrote in an English article entitled ‘The relation of forests to floods’ that China was ‘the only civilised country which has allowed deforestation to go on unchecked’ (Lin 1918, 485). While certainly questionable and already refuted by various recent academic works (Miller 2020; Zhang 2021), such a remark by a leading forestry scientist in early 20th century China pointed to the severity of deforestation at that time and its grave environmental consequences, including floods and land erosion, which are certainly not unconnected to the long tradition of timber construction in China. Even in the 21st century, direct opposition to promoting timber architecture is still publicly voiced. An article published in 2006, explicitly titled ‘Wood houses should not be advocated in China’, argued that China’s current timber resources could only sustain little more than half of its timber consumption. It also compared timber to fossil fuels: both were very scarce in China and potentially damaging the environment (Mu 2006).

Such a situation is comparable to the current promotion of great dams and hydroelectricity worldwide under the rhetoric of clean energy and global climate change, largely ignoring their potential damage to local ecology. As the American historian Christopher Sneddon has argued, ‘Climate change science and its (contested) prescriptions for generating ‘clean’ energy mesh well with a discourse of accelerated dam construction, while the equally compelling science of large rivers is only partially enrolled within this particular technopolitical network. Determining which science counts and receives technopolitical support is a highly selective process.’ (Sneddon 2015, 145) The current ‘climate change science’ also meshes well with the advocation of timber architecture and seems to disregard its potential environmental consequences. This research attempts to mitigate such an inadequacy from an architectural history perspective.

The prefabricated rural houses discussed in this paper, named ‘shuini nongfang’ (concrete rural houses) or ‘zhuangpeishi nongfang’ (prefabricated rural houses), resulted from both the state promotion of concrete structures through a planned economy and more importantly, the real ecological situation in the province which had hardly produced any construction-worthy timber since the 17th century. The situation was exacerbated by the Western embargo against the People’s Republic of China (PRC) and the devastating famine of 1959–1961, which cut off both international and interprovincial timber trade for Jiangsu. Still, most of these prefabricated concrete rural houses attempted to imitate vernacular timber rural houses in their design, which illustrates the lasting influence of China’s historic building practices with timber. These houses became dominant in some regions like Taixing County before being gradually replaced by multi-storey houses after the 1980s. During this comparatively brief period, the proliferation of prefabricated concrete rural houses blurred the line between vernacular and modern practices in Chinese architecture and emphasised the hitherto unacknowledged role of ecological and environmental crises in the modernisation of Chinese architecture.

2 Historical context: the depletion of wood in China and the early responses

Timber architecture has a long history in China, and it requires not only design skills but also abundant high-quality timber for construction. However, by the second half of the twentieth century, wood as a building resource in China had all but depleted. According to an official report in 1982, the per capita annual consumption of wood was 0.05 m³, merely 1/13 of the world average (Chen et al. 1982) (Fig. 1). The scarcity of wood was already felt in the 19th century when many large stately buildings from the late Qing Dynasty were entirely built from imported timber. In rural Jiangsu Province, like many other parts of China, timber was still used for construction in the early 20th century and sustained by interprovincial trade. The international and interprovincial trade of timber was the earliest response to the timber crisis in East China, but with international trade being cut off after the founding of the People’s Republic of China (PRC) in 1949 and the interprovincial trade was also affected by various factors, the depletion of timber was more strongly felt than ever in the late 1950s and the early 1960s.

Fig. 1

Per capita annual timber consumption (in m.³) in the 1970s (Source: diagram made by the author from the data in China Building Materials Academy 1972, 104 and Chen et al. 1982)

The stately buildings in late Imperial China were the first to feel the impact of the scarcity of wood. When the Qing Dynasty was recovering from the devastating civil war caused by the Taiping Rebellion (1851–1864), many stately buildings were built or rebuilt in the traditional way. However, the large logs that these buildings required were no longer available from what remained of the forests in China. Buying timber from Western colonial powers was at first only considered a stopgap solution before the recovery of the domestic timber trade, as in the case of the new Confucius Temple of Jiangning Prefecture in Nanjing, constructed in 1866–1871 (Mo and Gan 1874, vol.8, 3). However, by the early 20th century, the use of imported timber had become increasingly common. An article in The Far Eastern Review from 1911 recorded in detail how the pagatpat logs for the construction of the Mausoleum of Emperor Guangxu were ordered from an American businessman, Carl L. Seitz, who subsequently hewed them from dense mangrove forests in the American colony of the Philippines and transported them by a steamship to the port of Qinhuangdao (unknown author 1911). In addition, Seitz was at that time the head of the China Import & Export Lumber Co. (known in Chinese as Xiangtai Muhang), the biggest importer of foreign timber in China and an important provider of the timber used in lilong housings, a type of dwellings combined the features of vernacular courtyard houses in East China and British terraced houses prevalent in urban Shanghai (Tian et al. 2018, 77). Such imperial and colonial trading networks sustained the construction of imperial and humble timber buildings in different parts of China in the late 19th and early 20th centuries.

Jiangsu Province, the area studied in this research, had a relatively well-developed cement industry and numerous large concrete buildings in the nearby metropolises of Shanghai and Nanjing built in the first half of the twentieth century. The cultural reverence of wood, however, was deeply embedded in other parts of the province, especially in Jiangnan (the part of southern Jiangsu between Shanghai and Nanjing), which was one of the greatest consumers of timber in late Imperial China (Zhang 2021, 19–23). Although little construction-worthy timber was produced locally and vernacular builders had no access to imported timber, they were supplied by an interprovincial timber trade, which was documented in detail in Yingzao Fayuan (Original Laws of Construction), a manual of Jiangnan timber construction compiled in the 1930s.

Fir, the most common type of wood used for construction, came from Jiangxi, Hunan, Hubei and Fujian provinces. Timber from the former three provinces were all shipped to Jiangsu by the Yangtze River. Loggers tied the logs into huge rafts to be towed by boats and built cabins on them as living quarters. It was said that when many rafts were towed by sailboats, ‘the masts and sails were like forests, and the huge rafts almost covered the [Yangtze] River’ (Yao et al. 1986, 90). By the 1930s, small steamers were also used (Fig. 2). Due to the proliferation of interprovincial trade, the cultural reverence of wood and the lack of cement and concrete beyond the large metropolis, rural houses in Jiangsu were still largely built with vernacular timber structures throughout the first half of the 20th century.

Fig. 2

A large log raft towed by a small steamer on the Yangtze River, 1931 (Source: the author’s collection)

No academic research currently exists on the timber supply situation in East China after 1949, especially during the three years of famine from 1959 to 1961, but all evidence points to a dramatic change. In the mid to late 1950s, even large official buildings, like the Southwest Building of Nanjing University, could no longer secure proper timber and had to be constructed with undersized logs. In rural areas, the lack of timber was first acutely felt in the boat-building sector, which was vital to the livelihood of much of Jiangsu Province, as inland navigation was the major form of transport. After the successful mass production of ferrocement boats and ships in the early 1960s, the provincial Communist Party Secretary, Peng Chong, said with relief that ‘The life of Jiangsu has been saved by ferrocement boats.’ (Compilation Committee of Gazetteers of Jiangsu Province 2002, 93) With the recovery of the rural economy in 1962–1963, many farmers in East China have accumulated enough spare resources and were considering improving their living conditions. The lack of timber was then strongly felt in the housing sector (Building Installation Company of Jiangsu 1966, 27).

There are multiple possible explanations for this devastating blow to timber supplies in East China: Firstly, the Western embargo of the PRC meant a sharp decline in imported timber. Secondly, domestic sources of timber were probably depleted due to the numerous local construction projects during the Great Leap Forward in 1957–1958.¹ Timber was also exploited as fuel during the craze for iron smelting during the Great Leap Forward. Thirdly, the famine in provinces like Jiangxi, Hunan, and Hubei meant the obstruction of interprovincial trade in timber.

3 Modernism down to the countryside: the first attempt in introducing prefabricated concrete rural houses, 1961–1963

Starting from 1961, under the call of ‘putting design works on the track of aiding agriculture’, architects across China produced numerous designs for rural houses (Mu 1962). The most important aim of these new rural houses was to use concrete components to replace timber.² This task was easier for designers in Northern China, where vernacular houses often used load-bearing walls combined with relatively simple timber structures (Liu 1963; Mao 1963). In Jiangsu Province, where the most concrete rural house designs were produced, there were two strands: the designs with load-bearing walls and with concrete frameworks. The former was relatively successful, especially in Xuzhou, an area in the northmost tip of the province where vernacular rural houses were more akin to the northern types and one of few regions in China where triangular timber trusses were used since ancient times. The latter, however, made no attempt to imitate the vernacular timber structures and was not so popular.

Traditional Chinese timber frames were technically a prefabricated system, but concrete prefabrication was almost non-existent in China before the mid-1950s when it was introduced from the United Socialist Soviet Republics (USSR) and other Eastern Bloc countries, the socialist countries of Eastern Europe under the influence of the USSR. As a result, the newly introduced concrete prefabrication techniques were more similar to the building traditions of rural East China. In addition, compared with in-situ concrete structures, prefabricated concrete structures were more suitable for use in the countryside as the components were more easily produced and transported. Thus, all designs for concrete rural houses in the 1960s unanimously adopted prefabricated concrete structures. However, originally, most designers were heavily influenced by European designs and did not have much consideration for the building traditions in rural areas.

A collection of these European designs, mainly from East Germany, Poland and the USSR, was compiled and internally distributed by the Technological Intelligence Bureau of the Ministry of Building Construction in 1963 (Technological Intelligence Bureau of the Ministry of Building Construction 1963). Although this collection appeared two years after the beginning of rural house designs in Jiangsu, most of its content was from 1950s European journals, which might have previously been consulted by Chinese architects. The prefabricated concrete frameworks introduced in this collection were all very simple, and many were based on triangular trusses (Fig. 3).

Fig. 3

Two types of prefabricated concrete structure used in the USSR in 1958 (Source: Technological Intelligence Bureau of Ministry of Building Construction 1963, 15–16)

Concerning these European designs, architects in four different areas in Jiangsu Province, Xuzhou, Zhenjiang–Yangzhou, Nanjing and Wuxi, worked out different designs for local construction. Since Xuzhou was one of the few regions in China which had been building houses with triangular trusses for centuries, the task for local architects was arguably the easiest. Concrete triangular trusses, either cast as a whole or prefabricated in three parts, and concrete purlins replaced the vernacular timber trusses and purlins, with all other features, including load-bearing walls of rammed earth reinforced with bricks and stones, remaining unchanged. It is interesting to note how this very localised design was stylised to appear modern in an axonometric drawing published in Architectural Journal (Jianzhu Xuebao), the most prominent academic journal on architecture in post-1949 China. However, a similar drawing in a locally published pamphlet did not attempt to hide its vernacular characters (Li et al. 1963, 5; Xuzhou Architectural Design Office 1966) (Fig. 4).

Fig. 4

Two different renderings of the Xuzhou design from Architectural Journal and a locally published pamphlet (Source: Li et al. 1963, 5; Xuzhou Architectural Design Office 1966)

Architects from the other three areas where vernacular timber structural frames prevailed opted for two different solutions. In Wuxi, designers turned their focus to the highly developed native brick industry. They produced a very simple house dispensed with trusses and structural frames, the concrete purlins being directly borne by brick load-bearing walls (Jiang 1964). In Nanjing and Zhenjiang–Yangzhou, the designers decided to keep the principle of timber structural frames and produced concrete versions of them. However, instead of imitating vernacular timber frames, their designs clearly displayed the influence of modern European designs (Fig. 5).

Fig. 5

The Nanjing (left) and Zhenjiang–Yangzhou (right) designs, as appeared in Architectural Journal, both used concrete tiles (Source: Li et al. 1963, 5)

The modernist features of these early concrete rural houses were also reflected by other aspects of their designs. Designers in Nanjing considered concrete tiles, widely used since the 1930s in urban housings in Nanjing, to be better than the native clay tiles. As a result, the first 100 houses constructed in Babai Commune in Luhe Country near Nanjing in 1962 were all covered with concrete tiles (Li et al. 1963, 3–4; see Fig. 6 for examples of concrete tiles). In a publication from 1970, however, the concrete tiles were retrospectively criticised as ‘a waste of steel and cement and had inadequate insulation ability, making the living quarters too cold in winter and too hot in summer’ (Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 6).

Fig. 6

A typical vernacular timber structural frame in rural Nanjing and the associated terminologies used in this paper (Source: the author)

Another problem was the construction process. Although all designs were aimed at self-building by local farmers, only the Xuzhou and Wuxi designs with load-bearing walls could attain this objective. In Xuzhou, even the concrete trusses and purlins could be cast by the farmers themselves after some training (Jiang 1964, 22–23; Xuzhou Architectural Design Office 1966, 4–5). On the contrary, the 100 houses in Luhe County were all constructed by a professional construction team sent from Nanjing, so it was technically an urban collective housing project located in rural areas (Jiang 1964, 23; Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 6–8). Lessons from Xuzhou underlined the importance of creating several prototypes before large-scale construction to train local builders and demonstrate the concrete rural houses to the farmers who had never seen concrete buildings before and were suspicious of their viability (Xuzhou Architectural Design Office 1966, 4). This method was to be picked up by designers from Nanjing and other areas after 1964.

There are different estimations as to how many concrete rural houses were built across Jiangsu Province in 1961–1963, the number ranging from 2,300 to nearly 6,000 (Jiang 1964, 21; Building Installation Company of Jiangsu 1966, 27). There were incidental factors behind the success of concrete houses in Xuzhou, as the structure of traditional local rural houses was more similar to European houses, but the designers there were nevertheless pioneers in faithfully imitating vernacular rural houses and in promoting self-building. In contrast, architects in Wuxi were more resolute in breaking away from tradition. While successful, their designs were technically not prefabricated concrete houses and will not be included in the following discussions in this paper. The designs for Nanjing and Zhenjiang–Yangzhou, however, were stranded between the vernacular structural frames, the European designs and the pre-1949 urban houses and were generally unsuccessful. Only one year later did the designers entirely give up modern pretensions and began to imitate vernacular timber frames with concrete.

4 Imitating timber: the ‘Model Houses’, 1964–1965

To address the problems of the first batch of prefabricated concrete rural houses in Jiangsu Province, a new wave of survey and design began in November 1964 in the areas that adopted concrete framework designs in 1961–1963 (Building Installation Company of Jiangsu 1966, 27–30). This was when houses with prefabricated concrete frameworks that imitated timber structural frames eventually appeared in Jiangsu. The design and dissemination process of the rural houses around Nanjing was especially well documented in an Architectural Journal paper from 1966 and a pamphlet published in 1970. From these documentations, the Xuzhou example of building several prototypes as demonstrations were followed, and these prototypes were named ‘Model Houses’ (yangban zhuzhai) in Nanjing. Although the ‘Model Houses’, especially the most well-documented Zhou Guanggen’s House, were outspoken in their intention to copy vernacular timber structural frames, their joints still revealed strong influence from the European designs.

There were many different types of vernacular timber structural frames used in Jiangsu Province. However, apart from in Xuzhou, they were fundamentally the same in that no triangular trusses were used. This was also true for most other regions in China. Although some other Chinese researchers have used the term ‘trusses’ to denote these orthogonal timber structural frames, there were no load-bearing rafters like the real trusses in European or Xuzhou houses (Ren et al. 2018, 43–45). Figure 6 illustrates the terminologies associated with a typical vernacular timber structural frame in rural Nanjing, which also acted as the basis for the imitation of the prefabricated concrete ‘Model Houses’ in 1964–1965.

The first ‘Model Houses’ in Nanjing were designed and constructed in 1964 in four different types. One was a copy of the simple Wuxi design with load-bearing brick walls and concrete purlins, and two had concrete frameworks with Western-style trusses. The remaining one, Type D, was ostensibly trying to imitate the local vernacular timber structure but in a somewhat awkward way (Fig. 7). For example, all beams were formed by long ferrocement boards bolted onto the concrete columns, and the two stub columns were lengthened to reach the floor. Such a design was structurally feasible, but it only imitated the appearance of the vernacular timber frames. The four types of ‘Model Houses’ were open for review and criticism by the farmers. This probably informed the later, much more sophisticated design (Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 8–11).

Fig. 7

The Model House Type D in 1964 (Source: Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 11)

Subsequent development and dissemination of prefabricated concrete houses in rural Nanjing also followed the Xuzhou example. Even the name of the dissemination programme, ‘Technology Down to the Countryside’ (jishu xiaxiang), was directly copied from the Xuzhou programmes from 1962–1963 (Building Installation Company of Jiangsu 1966, 30–31; Xuzhou Architectural Design Office 1966, 4–5). The first house created by this program was built in Qilinmen Commune, Jiangning County, for a local farmer named Zhou Guanggen, which was also the first Model House that was built for an actual client (Fig. 8). Probably unconvinced by the earlier Model Houses, it was documented that several other farmers declined the invitation of becoming the first owner of a prefabricated concrete house before Zhou accepted it. Zhou’s house was relatively small, only two bays wide and had load-bearing stone gable walls and a prefabricated concrete structural frame in the centre. The stone walls were quarried and built by Zhou’s family and friends, while the prefabricated concrete structural frame was assembled by professional technicians as a demonstration for local builders and residents. The assembling took only three hours (Building Installation Company of Jiangsu 1966, 31; Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 9).

Fig. 8

The appearance and the concrete structure of Zhou Guanggen’s House (Source: Building Installation Company of Jiangsu 1966, 29)

The prefabricated concrete structural frame of Zhou Guanggen’s House greatly improved the Model House Type D. It did not only resemble the vernacular timber frames in its appearance but also, to a large extent, in its structure. Its components were smaller, lighter and more easily assembled (Fig. 9). However, the joints of this type of concrete structural frame still prominently displayed the influence of the European designs. Although in some parts, the traditional Chinese mortise-and-tenon joints were used, the major load-bearing joints between the beams and the main column were all pulled together by small steel or timber plates bolted onto the holes at the ends of the beams or simply by thick steel wires through the holes. Such a joint was prevalent in prefabricated concrete structures in the Eastern Bloc countries (Figs. 10 and 11).

Fig. 9

Drawing of the concrete structural frame used in Zhou Guanggen’s House (Source: Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 12)

Fig. 10

Different types of joints used in Zhou Guanggen’s House (Source: Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 17)

Fig. 11

Joints of prefabricated concrete rafters with thick steel wires, used in East Germany (1) and with small steel plates, used in Poland (2) (Source: Technological Intelligence Bureau of Ministry of Building Construction 1963, 9, 23)

Zhou Guanggen’s House was a major success, wholly satisfying its owner and making a significant impact in rural Nanjing. According to Zhou’s report, within 20 days after the completion of his house, more than 2,000 fellow farmers from his commune (township) came to visit. Orders for the ‘kits’ for self-building prefabricated concrete houses flowed from across Jiangning County to the local concrete prefabrication workshop. Not surprisingly, the prefabricated concrete structural frame of Zhou Guanggen’s House became one of the standard designs of prefabricated concrete rural houses in Nanjing, alongside two types of concrete trusses and concrete purlins for use with load-bearing walls (Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 9).

5 Changes and continuity: the development around Nanjing in the 1970s and beyond

Although exact data are unavailable, concrete purlins were almost certainly the most popular product from the 1961–1965 development in Jiangsu Province. They could be used freely alongside either timber or concrete structural frames or loading-bearing walls. By the late 1960s, prestressed concrete technology was also introduced into rural areas, and the concrete purlins could be made lighter and longer, further enhancing their popularity (Prefabrication Factory of Zhejiang Construction Company et al. 1971). This did not mean that prefabricated concrete structural frames fell out of favour, as in the two areas where I conducted fieldworks in 2021, Nanjing and Taixing, numerous rural houses from the 1970s and 1980s with either imitated timber structures or mixed concrete-and-timber structures were discovered. In rural Nanjing, all such houses surveyed were similar in design and could be considered the direct descendants of Zhou Guanggen’s House, although influence from other provinces, especially Zhejiang, was also present.

In Babaiqiao Township in Luhe District (former Luhe County), where prefabricated concrete rural houses were once built in 1962, relatively large numbers still existed when visited in 2021. Such houses existed both along the old commercial street and in Xiaojinshan Village, a planned rural settlement built in the early 1970s some 400 m to the south of the town (Fig. 12). The fact that such houses existed in both planned settlement and spontaneously-built commercial street indicated their acceptance by both the collective and individual households by the 1970s in Babaiqiao. In addition, many residents who had recently rebuilt their houses recycled the original prefabricated concrete components and reused them as pergolas and stands for hanging cloths. As in the later prefabricated concrete houses surveyed in Jiangning District and Taixing County, relatively little sign of decay was found in the concrete components despite their age.

Fig. 12

The concrete rural house surveyed at Xiaojinshan Village in Babaiqiao Township, Luhe District (Source: the author, photographed in 2021)

A disused house in Xiaojinshan Village provided an opportunity for a closer examination of the structure. At first sight, the structure was very similar to Zhou Guanggen’s House: the designs of concrete structural frames were identical, and the two-step beams were held by concrete corbels on the main columns and originally pulled together by steel wires or plates, holes for which could still be seen. However, a closer inspection revealed a significant difference. In Zhou Guanggen’s House, the stub column and the one-step beam were prefabricated together as an inverted-L-shaped component (Fig. 9, for terminologies, refer to Fig. 6), but here the stub column was cast together with the two-step beam, forming an inverted-T-shaped component. The one-step beams were not made of concrete but of timber (Figs. 13 and 14).

Fig. 13

Concrete framework of a house in Babaiqiao, two one-step beams were made of timber (Source: the author, photographed in 2021)

Fig. 14

Two-step beams held by concrete corbels and once pulled together with steel wires or plates through the small holes left on them (Source: the author, photographed in 2021)

Such a design was similar to a standard design of prefabricated concrete rural houses from neighbouring Zhejiang Province, widely publicised in the 1970s. The design and construction of prefabricated concrete rural houses in Zhejiang Province began in late 1962, and the first prefabricated rural house was built in Sujiacun Village, Linping District of Yuhang County (Xie 1962; Shen 1963). It is not known whether the standard design of a prefabricated rural house using prestressed concrete, envisaged in 1966 by Zhejiang Provincial Academy of Building Research and Linping Concrete Products Factory and named ‘Linping No.1’, was directly evolved from this first concrete rural house constructed in the same area four years earlier (China Academy of Building Research 1975, 24).

In 1975, ‘Linping No.1’ was described in detail in an internal publication of the China Academy of Building Research, Rural Housing Construction (Nongcun Fangwu Jianshe). To teach farmers the properties of the prestressed concrete components, an illustrated instruction of the correct ways to transport the components was also produced (China Academy of Building Research 1975, 24–26) (Figs. 15 and 16). The introduction of prestressed concrete could also explain the change in design, as the inverted-T-shaped components were more easily prestressed than the inverted-L-shaped components. In another publication from the same period, however, the prefabricated components of the same standard design were described as made without prestressing in Keqiao Township in Shaoxing, indicating the extent of local appropriation (China Architecture and Building Press 1974, 113–117).

Fig. 15

A diagram of Linping No.1 prefabricated concrete rural house from Rural Housing Construction (Source: China Academy of Building Research 1975, 25)

Fig. 16

Illustrations of the correct ways to transport the prestressed inverted-T-shaped main beams of Linping No.1 (Source: China Academy of Building Research 1975, 26)

While evidently influenced by the ‘Linping No.1’ standard design from Zhejiang, the prefabricated concrete houses at Babaiqiao still retained the basic structural design of Zhou Guanggen’s House and the rural timber houses in Nanjing. A similar tendency was detected in the towns that had purchased ‘kits’ for constructing concrete houses in 1964–1965. For example, in Shangfeng Township, Jiangning District (former Jiangning County), a house with only columns made of concrete was found (Fig. 17). This was very similar to the Taixing houses, which will be discussed in the next section, but even here the influence of Zhou Guanggen’s House was easily detectable. While the two two-step beams were now made of timber, they were not fixed to the main concrete column with traditional mortise-and-tenon joints. Instead, they rested on a steel plate cast within the main column which acted as corbels and were pulled together with thick steel wires (Fig. 18). Even with such a degree of vernacularisation, the joints that could be traced back to the 1950s European designs were still used by the rural builders who created this house.

Fig. 17

The concrete and timber structural frame of a rural house in Shangfeng (Source: the author, photographed in 2021)

Fig. 18

The joint between two timber beams and the main concrete column, showing the influence of the early 1960s Model Dwellings (Source: the author, photographed in 2021)

With obvious influence from the standard design in Zhejiang Province, the prefabricated concrete rural houses of Babaiqiao testified to the dynamics of interprovincial flows of technologies and designs in 1970s China. However, just like their far more vernacularised counterpart in Shangfeng, they were still rooted in both the vernacular timber houses of rural Nanjing and the early 1960s Model Houses. Most strikingly, even with all its beams reverted to timber, the house in Shangfeng still retained the joint from the European rural houses in the 1950s, clearly displaying a long and tortuous road of technology transfer and appropriation.

6 Compromise and localisation: the proliferation of concrete rural houses in Taixing, 1965–1980s

Both the prefabricated concrete rural houses that imitated vernacular timber structures and the houses with load-bearing walls and concrete purlins began to be supplanted by multi-storey houses in Jiangsu Province in the early 1980s. Although some recent studies have attributed the proliferation of modern multi-storey houses in rural China since the 1980s to the farmers’ intention to imitate urban houses (Ye and Huang 2016, 14), the state intervention in the name of saving farmland was at least equally important. This was especially true for southern Jiangsu. For example, a local regulation in Wujin County in 1981 banned the construction of single-storey rural houses except in ‘economically underdeveloped villages’ and emphasised that three- or four-storey residential buildings should be built in rural townships (People’s Government of Wujin County 1981, 11–12; see also Knapp 1992 for similar policies in other parts of China).

In northern Jiangsu, however, single-storey rural houses were still acceptable by the early 1980s and in at least one county, Taixing, the prefabricated concrete rural houses became the dominant type. Taixing was often cited in contemporary publications as an example of the successful dissemination of prefabricated concrete in rural areas. My interviews with residents revealed a landscape of localised prefabrication techniques, which differed greatly from the impression of modernity and efficiency created by officially published accounts. The combined concrete-and-timber structure prevailed here, and the concrete components were prefabricated with very simple techniques, often in the farmers’ backyards.

Taixing County has produced its designs of prefabricated concrete rural houses at least since the second wave of rural house designs in 1964–1965 (Building Installation Company of Jiangsu 1966). However, there is no information regarding this early design except for a plan and a simple structural diagram. The next mention of concrete rural houses in Taixing by official sources appeared 15 years later in an article by the Construction Material Industries Bureau of Jiangsu Province, which stated:

Taixing Concrete Products Factory (hereinafter TCPF) originally produced reinforced concrete structural frames with square columns (columns with square-shaped sections) to replace the traditional timber structural frames used by local farmers. However, the square columns were contradictory to local building tradition, so they did not sell well. This factory then replaced the square columns with hollow round concrete columns that are smoothly finished. When paint is applied, these look even better than timber columns, and caused a surge in sales. (Construction Material Industries Bureau of Jiangsu Province 1981, 10)

A similar, though retrospective, account exists in Gazetteer of Jiangsu Province: Construction Material Industries published in 2002, which used the products of TCPF as the example of modern prefabricated concrete rural houses that retained the vernacular timber structure of Jiangsu (Compilation Committee of Gazetteers of Jiangsu Province 2002, 111). However, the most remarkable claim was that the hollow round concrete columns produced by TCPF were made by centrifugal or spinning method. Centrifugal pipe columns have been used in Chinese architecture since the 1960s, but their main applications were in industrial buildings, multistorey urban housings and infrastructures such as electric poles (Building Construction Bureau of Sichuan Province 1977; Liu and Chen 1984). Applying such a modern industrial method to the prefabrication of rural houses immediately created an impression of industrial mass production. Furthermore, a paper published in 1981 even mentioned that TCPF had produced a set of standard designs for prestressed concrete components for rural houses, including not only concrete structural frames but also concrete window frames with iron bars (Fig. 19) and door frames (Chen 1981, 19).

Fig. 19

An example of a prefabricated concrete window frame in Taixing (Source: the author, photographed in 2021)

Fieldworks in Taixing, with the assistance of a local guide, Mr Xi Lu, confirmed the immense popularity of prefabricated concrete components in rural houses (Figs. 20 and 21). However, these houses had two distinctive features that were not mentioned or contradictory to the written accounts. While their columns were made of concrete, in most houses constructed in the 1970s and 1980s, the beams and purlins were all made of timber. In addition, contrary to the smooth finish mentioned in written accounts, most of the columns were crudely made. They were not round but were flat on the sides that faced the direction of the beams.

Fig. 20

A typical rural house in Taixing with ‘round’ concrete columns, timber beams, and purlins (Source: courtesy of Xi Lu, photographed in 2021)

Fig. 21

A rural house surveyed in Taixing that employed both ‘round’ and square concrete columns (Source: the author)

An interview with a resident revealed the actual construction process in the 1970s and 1980s. The interviewee confirmed the information from the 1981 article and pinpointed the transition from square to round columns in 1980. However, he explicitly denied the account that the columns were hollow or made by centrifugal method by describing in detail the real process of casting these concrete columns that we observed in the 1970s–1980s rural houses.

The columns were not directly bought from the concrete products factory but were constructed in the farmers’ backyards by the technicians sent from the factory. The technicians first dug a shallow ditch in the ground with a round-tipped shovel, forming a curved inner surface with the shovel tip and covering it with plastic film (used in the construction of greenhouses) to make it smooth. Then, bricks were piled along both sides of the ditch, forming the flat sides. After rebars were fixed inside, concrete was poured into this formwork of earth, bricks and plastic, and the other curved side was shaped by quickly moving a curved piece of plastic film from one end of the column to the other. When cured, The finished concrete column was removed from its earth-and-brick formwork and erected. Although the flat sides were coarse due to the contact with bricks, they were mostly hidden within partition walls.

Such a technique of on-site prefabrication with earth-and-brick moulds seemed to be a far cry from the industrialised mass production of round concrete columns with the centrifugal method, but it was not uncommon in rural China at that time. In fact, a set of photos illustrating almost the same technique of on-site prefabrication with earth-and-brick formworks existed in a 1972 document on the construction of concrete rural bridges in Jinshan County, Shanghai Municipality (Bridge Construction Team of Jinshan County and Highway Engineering Institute of Tongji University 1972, 9–10). The only difference was that lime mortar mixed with paper pulp, instead of plastic film, was used to smoothen the inner surfaces of the formworks (Fig. 22). This was understandable as, unlike domestic environments, the surfaces of bridges did not require such a high level of smoothness.

Fig. 22

Process of on-site prefabrication of a concrete truss for a bridge with earth-and-brick formworks in Jinshan County, 1972 (Source: Bridge Construction Team of Jinshan County in Shanghai Municipality and Highway Engineering Institute of Tongji University 1972)

It was also likely that the technicians casting concrete columns in the farmers’ backyards were not from TCPF. According to the Gazetteer of Taixing Industries, apart from TCPF, the state-run concrete products factory on the county level, other concrete products factories were set up on commune or township levels since the late 1960s. Subsequently, numerous small concrete products factories emerged after marketisation in the early 1980s. The number of concrete products factories in Taixing increased more than tenfold, from 21 in 1978 to 267 in 1990, while the number of workers only grew from 1,867 to around 3,600 (Compilation Committee of Gazetteer of Taixing Industries 1995, 125–126). These figures showed that most of these new ‘factories’ were small business ventures. Thus, it was rational for them to adopt a process of on-site prefabrication, which required little initial investment in factory buildings or machinery.

Another question regarding the houses in Taixing (and the one in Shangfeng Township, Jiangning) is why they were constructed with concrete columns but mostly had timber beams and purlins. Examples such as Zhou Guanggen’s House and houses in Babaiqiao demonstrated that, just like concrete columns, concrete beams could also be made to resemble timber components. However, the farmers’worries about the concrete components falling and hurting the inhabitants was a recurring theme in both contemporary publications and interviews (Revolution Committee of Nanjing No.2 Company of Jiangsu Infrastructure Bureau 1970, 7–8). The rural houses with concrete pillars and timber beams were most probably designed to address such concerns. Concrete, just like stone, performs better in resisting pressure than shear force. While reinforced and pre-stressed concrete had become increasingly common in rural China by the 1970s, relatively few ordinary farmers understood the properties of such materials and had faith in them. However, it was equally possible that such worries represented a deeply embedded, even subconscious, influence of the reverence of wood. Concrete, essentially a type of artificial stone, was considered unfit to encase a space occupied by living human beings. They were better suited for infrastructures and spaces for the dead, such as graves.

The prefabricated concrete rural houses in Taixing illustrated again the tension between modernity represented by the material of concrete and the actual situations in rural areas, which had already been shown by the development of concrete houses in 1961–1965. TCPF was ready to concede to the vernacular building methods and the farmers’ mentalities by producing round concrete columns which could be used in concrete-and-timber structural frames. Still, they attempted to maintain a sense of modernity by mass-producing the round concrete columns with the centrifugal method. However, this attempt faced a challenge from small ‘factories’ which were literally handmaking concrete columns in farmers’ backyards. Concrete had been fully transformed into a material freely manipulated by rural builders, and timber, an environmentally unsustainable material in East China, had finally been replaced in rural construction.

7 Conclusion

The negative environmental and climate impact of producing and using cement and concrete has been widely acknowledged, and this research does not propose to argue that concrete is still a sustainable material in today’s China, where its overuse has caused grave global consequences. Instead, this research has revealed why some parts of China had abandoned the long and revered tradition of timber architecture and turned to concrete structures in the second half of the twentieth century. With the development of the cement industry in East China that exploited the abundant local resources of limestone since the early twentieth century and especially after the fast industrialisation in the 1950s, cement and concrete became more abundant and were considered a response to an ecological crisis caused by deforestation and the lack of timber. Instead of imitating modernist designs, the prefabricated concrete rural houses represent a continuation of vernacular designs and construction techniques, which eventually enabled the concrete houses to be accepted by the farmers and successfully replaced vernacular timber houses. Such a process of vernacularisation and technological appropriation still provides lessons for promoting eco- and climate-friendly building materials and technologies, especially in rural areas.

However, the widespread construction of prefabricated concrete rural houses in East China, one of China’s wealthiest regions, certainly prepared grounds for the mass production and consumption of concrete in China since the 1980s and thus contributed indirectly to the current global climate emergency. So, this research also reveals a paradox: One generation’s response to their environmental and ecological crises became the root of the next generation’s climate crisis. Today, timber buildings have returned with an environmental and climate rhetoric, which is that timber structures have low carbon emissions and a high potential for carbon fixation. However, the problems that caused the abandonment of timber buildings in much of China in the twentieth century, including floods and other ecological disasters caused by deforestation and the volatile international supply chain of timber (which is also potentially high in carbon emission), have not been solved. Such a paradox of environmental and climate crises and human responses is perhaps unavoidable. Still, it might also be avoided with a more sophisticated reconsideration of the environmental impact of different materials, which invites careful investigations and analyses of both positive and negative lessons from architectural history and heritage.