Roofing in China

China has one of the longest continuous roofing traditions in the world. Its classical architecture is a timber architecture in which the roof, heavy, tiled and often curved, is the most expressive element, and for more than two thousand years the form, colour and ornament of a roof signalled the rank of the building beneath it. Today most new buildings are reinforced concrete with flat, membrane-waterproofed roofs, and industrial buildings use large areas of profiled steel.

Climate and hazards

China spans climates from the cold, dry north and the high Tibetan Plateau to the humid subtropical south. Roofs must shed heavy monsoon rain across the south and east, carry snow in the north and north-east, and resist typhoon winds on the south-east coast. Much of the country is seismically active: the Tang-period Great Buddha Hall of Nanchan Temple in Shanxi was damaged by an earthquake in 1966, and the flexibility of traditional bracketed timber frames is widely credited with helping old halls survive earthquakes. Fire was a constant urban danger, which shaped tile roofs, firewalls and even roof ornaments believed to ward off fire.

Roofing history

Neolithic and Bronze Age. According to a 2023 study, the oldest known composite tiled roofs come from Qiaocun, on the edge of the Loess Plateau in north-west China. Excavations recovered several thousand pieces of fired clay tile, radiocarbon dated to about 2400-2200 BCE, in the early Longshan period. A 2023 study reconstructed how semi-cylindrical cover tiles and trapezoidal pan tiles were combined on a roof, the same pan-and-cover principle that Chinese roofs still use. Tile making developed substantially in central Shaanxi during the Western Zhou dynasty (1046-771 BCE), and the technology later spread to Korea, Japan, the Russian Far East and South-East Asia.

Bracketing and the imperial roof. Interlocking timber bracket sets (dougong) emerged in early forms under the Western Zhou and were widely used by the Spring and Autumn period (770-476 BCE). They reached their greatest structural complexity under the Tang and Song, carrying deep eaves out beyond the columns. China's oldest preserved timber building, the Great Buddha Hall of Nanchan Temple (782), has a hip-and-gable roof on bracket sets; the East Hall of Foguang Temple (857), a hall of seven by four bays measuring 34 by 17.7 m (110 by 58 ft), has a hipped roof and was identified by Liang Sicheng and Lin Huiyin's survey team in 1937.

Glazed tiles and standardisation. Glazed roof tiles were in use by the Tang dynasty. In 1103 the Song court published the Yingzao Fashi, a 34-chapter building manual compiled by Li Jie, which set an eight-rank system for timber member sizes, gave rules for tiling and the mixing of glazes and mortars, and standardised ridge ornaments. Song tiling practice overlapped plain tiles by about 40 per cent; by the Qing dynasty the standard overlap had risen to about 70 per cent, so a cracked tile would no longer leak.

Ming and Qing. Under the Ming (1368-1644) and Qing (1644-1911) yellow glaze became reserved for the emperor, and the Forbidden City in Beijing, built in 1406-1420, became the supreme example of a ranked roofscape. After the Song, bracket sets became smaller, more numerous and more decorative.

Modern era. In the 20th century reinforced concrete, flat roofs and later steel and membrane systems replaced tiled timber roofs in most new building, while traditional roofs survive on temples, heritage districts and rural houses.

Traditional and vernacular roofs

• Hierarchy of forms. Hip roofs, sloping on four sides, were reserved for the emperor, in single- or double-eaved forms; the Hall of Supreme Harmony has a double-eaved hip roof. The hip-and-gable roof (xieshan) ranked next and became the classic form across East Asia. Gabled roofs were the everyday form, and single-slope roofs the cheapest.
• Sweeping roofs that rise at the corners were usually reserved for temples, palaces and wealthy households.
• Siheyuan courtyard houses of Beijing and the north have grey-tiled gabled roofs around a central yard.
• Fujian tulou, the large earthen clan houses of south-west Fujian, carry continuous tiled roofs with eaves about 2 m (6.5 ft) deep to protect rammed-earth walls from rain.
• Firewalls such as the horse-head walls (matouqiang) of the south rise above roofs to stop embers spreading.
• Southern Fujian (Hokkien) temples and mansions use upswept swallowtail ridges, a style also typical of Taiwan.
• Ridge ornaments. Ridge-end beasts (chiwen), descended from the earlier bird-tail chiwei of the Han period, were believed to protect against fire. Imperial hip ridges carry lines of glazed figures whose number reflected rank.

Roofing today

Most urban buildings are reinforced concrete with flat roofs waterproofed by modified-bitumen or polymer membranes and coatings, often with protective layers or tiles above. Industrial and commercial buildings use profiled steel sheet and metal panel roofs. Tiled pitched roofs remain common on rural houses and on buildings in historic styles.

Codes, standards and regulation

Roofing is governed by national GB standards issued by the Ministry of Housing and Urban-Rural Development. GB 50345-2012, Technical Code for Roof Engineering, in force since 1 October 2012, covers membrane and coating flat roofs, tiled pitched roofs, metal panel roofs and planted roofs. GB 55030-2022 is a mandatory general code for building waterproofing.

Industry

China is a very large producer and user of roofing materials, from clay and concrete tiles to bitumen membranes and coated steel coil.

Notable roofs

• Forbidden City, Beijing (1406-1420; UNESCO World Heritage, 1987) - yellow-glazed roofs ranked by form and ridge figures.
• Foguang Temple East Hall (857) and Nanchan Temple Great Buddha Hall (782), Shanxi - the oldest surviving timber roofs in China; Foguang is part of the Mount Wutai World Heritage site (2009).
• Temple of Heaven, Beijing - blue-glazed roofs symbolising the sky.
• Fujian tulou (UNESCO, 2008) - 46 earthen buildings with wide-eaved ring and square roofs.

Local roofing terms

• dougong (斗拱) - bracket set of blocks and arms
• xieshan (歇山) - hip-and-gable roof
• liuli wa (琉璃瓦) - glazed roof tile
• chiwen (蚩吻) / chiwei (鸱尾) - ridge-end ornament
• matouqiang - horse-head firewall

Sources and gaps

National statistics on roofing materials and manufacturer data: published information is limited.