Discovery and Science Channel’s How It’s Made Fibre Cement Siding episode.
Fiber cement siding (or “fibre cement cladding” in the UK and Australasia) is a building material used to cover the exterior of a building in both commercial and domestic applications. Fiber cement is a composite material made of sand, cement and cellulose fibers.
In appearance fiber cement siding most often consists of overlapping horizontal boards, imitating wooden siding, clapboard and imitation shingles. Fiber cement siding is also manufactured in a sheet form and is used not only as cladding but is also commonly used as a soffit / eave lining and as a tile underlay on decks and in bathrooms. Fiber cement siding is not only used as an exterior siding, it can also be utilized as a substitute for timber fascias and bargeboards in high fire areas.
Sheet sizes vary slightly from manufacturer to manufacturer but generally they range between 2400 – 3000 mm in length and 900 –1200mm in width (600 & 450 mm increments). This manufactured size minimizes on-site wastage as residential floor, wall and roof structures lay structural members at 450 or 600 centres.
When used as siding boards, widths between 130mm and 300mm (5.25 inch to 12 inch) are available.
Fibre cement thicknesses vary between 4.5-18mm and also vary in density – the lower density resulting in a fibrous rough edge when cut and the higher density having a cleaner smoother edge when cut.
Thermal resistance and sound transmission vary greatly between fiber cement products. Fiber cement sheet products rate poorly in thermal resistance and sound transmission and separate wall insulation is highly recommended. Generally the thicker and denser the product the better resistance it will have to temperature and sound transmission.
The external cladding products require very little maintenance once installed and painted. The thicker/denser fiber cement products have excellent impact resistance but the thinner less dense products need to be protected from impact. Compared to wooden siding, fiber cement is not susceptible to termites or rot.
Fibre cement siding using base board materials that have been classified, by accredited laboratories, as Category A according to BS EN 12467: 2004 Fibre-cement flat sheets – Product specification and test methods are sidings which are intended for applications where they may be subject to heat, high moisture and severe frost.
Fibre cement cladding is a non combustible material which is widely used in high bush fire prone areas throughout Australia . Pictured above is James Hardie’s Fiber Cement cladding ‘Scyon Linea’ weatherboard which has been substituted for the traditional timber fascia and barge board materials.
While the best possible Reaction to Fire Classifications are A1 (construction applications) and A1Fl (flooring applications) respectively, both of which mean “non-combustible” according to European standard EN 13501-1: 2007, as classified by a notified laboratory in Europe, some fibre cement boards only come with Fire Classification of A2 (limited combustibility) or even lower classifications, if they are tested at all.
As mentioned previously, long-term exposure to silica dust generated by cutting fiber cement siding during installation can lead to silicosis and other lung diseases among workers. Researchers at the National Institute for Occupational Safety and Health (NIOSH) confirmed these findings, showing that many of the silica dust particles are in the respirable fraction, able to penetrate the deepest parts of the lung. Laboratory tests performed by cutting fiber cement siding within an isolated chamber showed that by connecting a regular shop vacuum to a circular saw, exposures to silica dust produced by the cutting can be reduced by 80-90%.