Hardie Board and Fiber Cement Siding

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Hardie Board is fiber cement siding manufactured by James Hardie Building Products, one of the first successful manufacturers of this material. Two of their most popular products are HardiePlank® (horizontal lap siding, 0.312 inches thick) and HardiePanel® (vertical siding, 0.312 inches thick). The fiber cement siding is made from Portland cement mixed with ground sand, cellulose fiber, and other additives. The product is also known as cement-fiber siding, concrete siding, and fiber cement cladding.

Fiber cement siding can resemble stucco, wood clapboards, or cedar shingles (e.g., HardieShingle® 0.25 inches thick), depending on how the panels are textured during the manufacturing process. Pulverized sand, cement, and wood pulp are mixed with water to make a slurry, which is rolled out and pressed together into sheets. The water is squeezed out, a pattern is pressed onto the surface, and the sheets are cut into boards. The product is baked in autoclaves under high-pressure steam, and then the individual boards are jostled apart, tested for strength, and painted. It may look like wood, but the boards are much heavier with properties associated more with cement than wood. The wood fiber is added to give the board flexibility so it doesn't crack.

The material is more durable than most woods and stucco and resists insects and rot. It is also fire resistant, which explains its early popularity in Australia, an arid land plagued by wildfires throughout the bush.

Fiber cement siding has become popular, because it requires little maintenance, will not melt, is non-combustible, and can have a natural, wood-like appearance. However, many people say it is much more difficult for a nonprofessional to install than other siding. Remember, when you're cutting it that it's really cement, with the associated hardness and dust to prove it.

Hardie Board should not be confused with "hardboard," which is dense, pressed particleboard made from wood. Common misspellings include hardiboard, hardyboard, hardyplank, hardypanel, HardiPlank, and HardiPanel. Knowing the manufacturer's name will help with accurate spelling. James Hardie Industries PLC is headquartered in Ireland.

Expense Comparisons

Although more expensive than vinyl, fiber cement siding is considerably less expensive than wood. Fiber cement board is generally less expensive than cedarwood, more expensive than vinyl, and less expensive than brick. It is equal or less expensive than composite siding and less expensive than synthetic stucco. As with any construction project, the materials are but one aspect of the expense. Installing fiber cement board incorrectly can be a priceless mistake.

About James Hardie

James Hardie Building Products has long been associated with Australia, ever since the Scottish-born son of master tanner Alexander Hardie emigrated there in the late 19th century. James Hardie became an importer of tannery chemicals and equipment until he came upon a new fire-resistant product being manufactured by the French Fibro-Ciment Co. The construction product became so popular so quickly that even the misspelled name Hardi Board became somewhat generic, like "Kleenex" means facial tissues and "Bilco" means any steel cellar doorway. "HardieBoard" has come to mean any fiber cement siding by any number of suppliers. The success of the fibro-cement sheeting imported by Hardie allowed him to sell his company and his own name.

Hardie Fibrolite

Fibrolite is synonymous with asbestos in places like New Zealand and Australia. Asbestos cement sheets became popular in the 1950s as an alternative building material to wood and brick. Hardie manufactured a cement-asbestos product in Australia beginning in the early 20th century. The James Hardie company continues to settle claims with employees and customers who have been subject to asbestos-related cancers presumably from working closely with the building product. Since 1987, Hardie products have not contained asbestos; the fiber replacement is organic wood pulp. James Hardie building products installed before 1985 may contain asbestos.

Fiber Cement Building Products

James Hardie Building Products is a company that specializes in fiber cement building materials and has come to dominate the market, yet other providers carry products similar to Hardie Boards. For example, allura USA bought CertainTeed Corporation and also merged its manufacturing with Maxitile in order to be competitive. American Fiber Cement Corporation (AFCC) distributes in Europe under the name Cembrit. Nichiha has a formula that uses less silica and more fly ash. Wonderboard® by Custom Building Products is a product similar to HardieBacker,® a cement-based underlayment.

Fiber cement cladding has a history of expanding, shrinking, and cracking. James Hardie has addressed these issues with the HardieZone® system. In the U.S. a different formula is used to make siding for homes in the north subject to freezing temperatures as opposed to siding for homes in the south, subject to hot, wet climates. Many residential contractors cannot be convinced that cement siding is even worth changing their building processes.

Next Generation Concrete Cladding

Architects are using Ultra-High-Performance Concrete (UHPC), a very expensive, cement-based product for commercial cladding. Popularly known by their fabricators, such as Lafarge's Ductal® and TAKTL and Envel with Ductal, UHPC is a complex recipe that includes metal fibers of steel in the mix, making the product super strong but thin and shapeable. Its durability exceeds other cement mixtures, and it's not subject to some of the fiber cement hazards such as expanding and shrinking. Building on UHPC, the next generation of composite technology is DUCON® Micro-Reinforced Concrete Systems; stronger, thinner, and even more durable for structures in an age of terrorism and weather extremes.

Concrete homes have long been considered a solution to building in climates of extremes. Like most new products for the homeowner, look to what architects are using to eventually be the product of choice, as long as you can find a contractor who keeps up with the skills and necessary equipment to install it.


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Craven, Jackie. "Hardie Board and Fiber Cement Siding." ThoughtCo, Aug. 26, 2020, thoughtco.com/what-are-hardieplank-hardiepanel-178360. Craven, Jackie. (2020, August 26). Hardie Board and Fiber Cement Siding. Retrieved from https://www.thoughtco.com/what-are-hardieplank-hardiepanel-178360 Craven, Jackie. "Hardie Board and Fiber Cement Siding." ThoughtCo. https://www.thoughtco.com/what-are-hardieplank-hardiepanel-178360 (accessed June 6, 2023).