Fiber cement siding

Hardipanels on design-build addition, Ithaca NY)

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.

Usage

Fibre cement is a composite material made of sand, cement and cellulose fibers. In appearance fibre cement cladding most often consists of overlapping horizontal boards, imitating wooden cladding, 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.

File:Domestic use hardipanels.jpg

CSR Fiber Cement sheet cladding - dwelling addition, Hardys Bay, NSW, Australia

Fiber cement cladding is not only used as an exterior cladding, it can also be utilised as a substitute for timber fascias and barge boards in high fire areas.

Specifications

Fibre cement sheeting products are manufactured in Australia by CSR, BGC and James Hardie in accordance with Australian Standard 2908.2000, "Cellulose Cement Products". Fiber cement siding and sheeting is produced in the United States by CertainTeed Corporation.

Sheet sizes vary slightly from manufacture to manufacture but generally they range between 2400 – 3000mm in length and 900 –1200mm in width (600 & 450mm increments). This manufactured size minimises on-site wastage as residential floor, wall and roof structures lay structural members at 450 or 600 centres.

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 great 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 more dense the product the better resistance it will have to temperature and sound transmission.

Installation

Fibre cement cladding is a very heavy product and requires 2 men to carry the uncut sheets. Thin fibre cement cladding is fragile before installation and must be handled carefully; it is prone to chipping and breakage if improperly handled.

Once the product is cut it may again require 2 men to install – one to hold the sheet flush against studwork and the other to nail the product in place.

Cutting fibre cement cladding sheeting usually requires a mechanised saw or metal hand shears and sheets can be cut to size in three ways:

Thinner sheets can be scored with a heavy duty cutting blade and snapped
Purpose made "fibro cutter" (an Australian term)
Thicker and more dense sheets require cutting by a mechanical saw

Some caution must be exercised to properly ventilate areas where FCS is being cut; long-term exposure to the silica dust generated during the installation process can cause silicosis.

Fibre cement cladding can be painted before or after installation. (For areas of exposure, weatherproof paint must be used.) Once the product is fixed the joins are usually covered with timber battens and the entire wall surface is painted.

History

Fibre cement products came about as a replacement for the widely used "Asbestos Cement Sheeting" product manufactured by "James Hardie" until the late 1980s.

Durability

The external cladding products require very little maintenance once installed and painted. The thicker/denser fibre cement products have excellent impact resistance but the thinner less dense products need to be protected from impact.

Fire Resistance

Fibre cement cladding is a non combustible material which is widely used in high bush fire prone areas throughout Australia . Pictured above is CSRs' Fiber Cement cladding ‘Linea’ board which has been substituted for the traditional timber fascia and barge board materials.

Alternatives

Competitors to fibre cement cladding are imitation clapboard include vinyl, PVC, wood composite products and aluminum siding. Compared to wooden siding, fiber cement is not susceptible to termites or rot.