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 underlays 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.
Specifications
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 600mm centres.
When used as siding boards, widths between 130mm and 300mm (5.25 inch to 12 inch) are available.[4] Fiber 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 can 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.
Fiber cement cladding is a very heavy product and requires two people to carry the uncut sheets. Thin fiber cement cladding is fragile before installation and must be handled carefully because it is prone to chipping and breakage if improperly handled. Once the product is cut it may again require two people to install – one to hold the sheet flush against studwork and the other to nail the product in place.
Cutting fiber cement sheeting:
Sheeting can be cut to size in three ways.
• Thinner sheets can be scored with a heavy duty cutting blade and snapped
• Using a hand- or electric-powered "fibro cutter" (Australian term)
• A mechanical saw using a diamond blade (masonry blade) is needed to cut thicker and denser sheets
When hanging fiber cement sheets, an approximately 5-millimetre (0.2 in) gap is required between end-joints (cladding seams), later to be filled with caulking made for fiber cement siding. Metal 150 mm × 150 mm (6 in × 6 in) step flashing is required behind overlapping seams to prevent sheathing damage from water. Hot-dipped galvanized roofing nails are used to secure the sheets.
Some caution must be exercised to properly ventilate areas where fiber cement siding (FCS) is being cut; long-term exposure to the silica dust generated during the installation process can cause silicosis.
Fiber cement cladding can be painted or stained before or after installation.[2] For areas of exposure, weatherproof paint must be used. Once the product is fixed the joints are usually covered with timber battens and the entire wall surface is painted.
