Asbestos-Cement Roofing

Asbestos-cement roofing is roofing made from a composite of Portland cement reinforced with asbestos fibres, pressed into corrugated sheets, flat sheets, slates and moulded fittings. It was used worldwide through much of the 20th century on houses, garages, farm buildings and factories. Today it is recognised as a health hazard, its manufacture and use are banned in many countries, and its removal is tightly regulated. In Australia and New Zealand it is widely known as fibro; other names include AC sheet and, after an early brand, Eternit.

History

Austrian Ludwig Hatschek patented his asbestos-cement process in 1900 (some sources give 1901) and gave the product the trade name Eternit in 1903. His process mixed about 90% Portland cement with 10% asbestos fibre and water and formed thin sheets on a machine adapted from cardboard-making. The material was marketed as a cheap, fireproof alternative to asphalt and other roofing, and corrugated profiles such as "Super Six" became standard on industrial and agricultural buildings. Products were also made to imitate slate, and Europe produced a wider variety of shapes than the United States.

Health hazard

Intact, well-bonded asbestos cement releases few fibres, but weathering, breakage, drilling, cutting, abrasion and pressure-washing can release them into the air. As the material ages it becomes brittle and more friable. Inhaled asbestos fibres cause or increase the risk of asbestosis and of pleural and peritoneal mesothelioma. Queensland, Australia, for example, prohibits cleaning fibro roofs with pressure washers.

Bans by country (selected)

• United Kingdom: blue and brown asbestos banned in 1985; white (chrysotile) asbestos banned in Great Britain in 1999 and Northern Ireland in 2000.
• Australia: nationwide ban on import and use of all asbestos from 31 December 2003 (materials already installed were not covered).
• New Zealand: raw amphibole asbestos imports banned 1984; chrysotile imports banned 2002.
• Japan: full ban 2004.
• South Korea: full ban from January 2009.
• Brazil: nationwide prohibition by the Supreme Federal Court in November 2017.
• Canada: import, sale and use of most asbestos products prohibited from 30 December 2018.
• United States: in March 2024 the Environmental Protection Agency finalised a rule banning the ongoing uses of chrysotile asbestos, the only form still imported or used in the country, with phase-out periods for remaining industrial uses. The rule covers ongoing uses; asbestos already in buildings is addressed separately.
• European Union member states have also banned asbestos.
• In parts of South America and Asia asbestos-cement sheets remain common on existing buildings, and India has continued to use asbestos widely.

Removal regulations

Rules vary widely, so owners should check local law before disturbing any suspect roof. In Great Britain the Control of Asbestos Regulations 2012 require duty holders of non-domestic buildings to manage asbestos, and set notification, record-keeping and health-surveillance requirements for certain work; higher-risk materials must be removed by licensed contractors. Australia's national codes set out management and removal practices, with state regulators enforcing them.

Replacement

Asbestos-free fibre cement, reinforced with cellulose fibres, replaced asbestos cement from the 1980s and is still widely made for slates and corrugated sheets.