Roofing in Singapore

Singapore is a small, dense tropical city-state that transformed its housing within two decades, from timber kampong houses roofed with palm-leaf attap or zinc sheet to high-rise public housing blocks with flat concrete roofs. Many of those roofs now carry solar panels under a national programme, alongside extensive rooftop greenery.

Climate and hazards

Singapore is equatorial: hot, humid and rainy all year, with heavy convective storms and periodic droughts. It is not in a typhoon or major earthquake zone. The main roof concerns are rain shedding and drainage, heat gain and, historically, fire.

Roofing history

Kampong houses. Late 19th- and early 20th-century kampong (village) houses had tall, pitched, gabled roofs covered in attap, made from palm fronds, over raised floors that helped with airflow, flash floods and damp ground. Attap insulated well but became dry and brittle in heat waves and droughts.

Fire and zinc. From the 1950s many attap roofs were replaced with zinc sheeting. Urban squatter settlements, which grew from about 127,000 people in 1947 to 246,000 in the mid-1950s, were densely packed with attap- or zinc-roofed huts. Major fires struck Kampong Bugis (1951), Geylang (1953), Kampong Tiong Bahru (1955 and 1959) and Kampong Koo Chye (1958). On 25 May 1961, the Bukit Ho Swee fire destroyed 19 ha (47 acres) of homes and left more than 16,000 people homeless.

Public housing. The Housing and Development Board (HDB) was formed on 1 February 1960, taking over from the Singapore Improvement Trust. After the Bukit Ho Swee fire the government promised to rehouse the victims in HDB flats, and a new estate was built on the site by February 1962. Public housing and urban renewal from the 1960s caused a sharp decline in attap- and zinc-roofed houses: they made up 34% of homes in 1970 and 10.8% at the 1980 census, mostly in outlying areas.

Traditional and vernacular roofs

• Attap house: timber kampong house with a steep gabled attap roof (see the attap roof entry).
• Zinc-roofed house: the 1950s-1970s successor, with corrugated zinc sheet replacing thatch.

Roofing today

A large share of Singapore's population lives in HDB blocks, whose flat reinforced-concrete roofs are used for water tanks, services, greenery and solar panels.

Rooftop solar. HDB began installing solar panels on blocks in the 2010s and launched the SolarNova programme with the Economic Development Board in 2014. By December 2019 about 2,060 HDB blocks had solar panels, with about 2,500 more in progress. In 2019 HDB raised its target to 540 MWp by 2030 (from 220 MWp, already exceeded), as part of a national goal of at least 2 GWp, enough to generate about 648 GWh a year.

Rooftop greenery. National incentives support green roofs on new and existing buildings (see Singapore skyrise greenery).

Design heritage. The natural cross-ventilation of the attap house inspired contemporary designs such as Newton Suites by WOHA Architects.

Codes, standards and regulation

Rooftop greenery is promoted by the National Parks Board and the Urban Redevelopment Authority.

Notable roofs

• HDB estates with continuous rooftop solar arrays.
• Rooftop gardens under the skyrise greenery programmes.

Local roofing terms

• attap (Malay atap) - palm-leaf thatch; also "roof"
• kampong - village
• zinc roof - local term for corrugated galvanised steel sheet

Sources and gaps

A summary of the national building control law as it applies to roofs, details of shophouse roofing and industry data: published information is limited.