Corrugated Bitumen Sheet

A corrugated bitumen sheet is a light, wavy roofing panel made from organic fibres saturated with bitumen and coloured on the surface. It is widely used on garden sheds, carports, stables, lean-tos and farm buildings, and as an under-layer beneath tiles in some systems. The product type is often called by the best-known brand name, Onduline, which originated in France and states that it has been making such products for about 80 years.

Composition

Sheets are made from a mat of cellulose fibres, derived from wood, impregnated with bitumen and formed into corrugations. One manufacturer states that its sheets contain about 45-51% recycled material.

Typical properties

Using one widely sold product as an example:

• Size: 2,000 by 950 mm (about 79 by 37 in), covering 1.9 m² (20.5 ft²) per sheet.
• Thickness: 3 mm (about 1/8 in).
• Weight: about 6.4 kg (14 lb) per sheet, or roughly 3.4 kg/m² (0.7 lb/ft²), far lighter than fibre cement or tile.
• Profile: 10 corrugations about 38 mm (1.5 in) high at 95 mm (3.7 in) centres.
• Minimum pitch: 5°, with a full supporting deck required below 10°.
• Fire: reaction-to-fire Class E under the European system, meaning it is combustible.

In Europe, corrugated bitumen sheets are covered by the harmonised product standard EN 534.

Advantages

• Light and easy to cut, carry and fix, so it is popular for DIY work.
• Does not rust and is quieter in rain than thin metal sheet.
• Low cost compared with most other roofing.

Limitations

• Manufacturer waterproofing warranties are relatively short (15 years for one leading product), reflecting a shorter service life than tile or metal.
• The sheets are combustible (Class E), which needs to be considered where building regulations control fire spread.

Related products

The same manufacturers make corrugated bitumen "tile-effect" sheets and small bitumen tiles that imitate clay roofing.