Fiber Cement Siding – What You Need to Know

Fiber-Cement Siding is termite resistant, durable, non-combustible, easy to install and finish, moisture resistant, and typically carry 50 year manufacturer’s warranties. Fiber cement siding has the appearance of wood siding but it is lower priced and has lower maintenance costs than wood siding. Fiber cement siding is manufactured by many large building materials manufacturer’s, and is available in a wide variety of colors, styles, textures, patterns, and sizes. Typically, fiber cement siding products cost more than vinyl siding, but costs less than masonry, wood, and stucco cladding.

The concept of fiber cement siding has been in existence for nearly a century. Initially the fiber cement siding had an asbestos admixture. In the last 20 years newer technologies began making the product as we know it today in a different manner. The siding is composed of Portland cement, sand, cellulose or wood fiber material that has been autoclaved, which means it has been cured with pressurized steam to increase its strength and dimensional stability. The fiber content helps make the cement stronger by avoiding and eliminating cracking, which typically occurs with cement as it ages.

The following is a partial list of producers and suppliers of fiber-cement siding:

o Cemplank

o Certainteed

o GAF Materials

o James Hardie

o MaxiTile

o Nichiha USA

It is quite common that many refer to this product as “hardie board”, for the namesake, although there are other large producers of fiber-cement siding. Fiber cement products also include soffit, trim, and flashing materials.


There are many advantages of fiber cement siding with the largest being its durability and characteristics that lend its installation to any geographic region and climate. The product is more versatile than vinyl or wood siding alternatives. The fiber cement products are thicker than vinyl siding and therefore are more resistant to peeling, cracking, chipping, shrinking, swelling, sagging, and bowing. Additionally, it is less prone to wind storm damage and wind borne debris damage. The product functions well in southwest climatic heat conditions and the brutal cold of the New England states. It also is naturally resistant to fungus, mildew, termites, there is not routine maintenance required in order to prevent these problems as is the case with wood siding. The product also has the ability for paint to easily adhere to its surface and resist moisture, which is very helpful in southern regions.


The advantages far outnumber the disadvantages of the product, although here are some drawbacks:

o The siding is heavy and proper handling and care is required prior to installation.

o An ingredient of the products is Silica (SiO 2) which also comprises approximately 75% of the earth’s crust and is a very common ingredient in most products in the tile and masonry industries. When silica is in an intact state it does not pose any silica risk. Although when cut, drilled, or grinded during the installation process, the resulting smaller, silica containing dust can pose a potential health hazard as inhalation of excessive quantities over extended time periods can cause silicosis, lung cancer, or other lung related diseases. Inorder to eliminate any health problems, both OSHA, NIOSH, and the manufacturer’s recommend wearing a properly fitted respirator to protect against any potential health risks.

o The products can be installed by homeowners, although professional installation is recommended to conform to manufacturers recommendations and guidelines. Noncompliance with the installation specifications typically will lead to problems and dissatisfaction.

o Improper installation techniques generally relate to improper nailing, lack of proper flashing methods, improper clearances from other surfaces – i.e. roof and foundation areas, caulking, painting, no moisture resistant barrier beneath the siding installation.

Most manufacturer’s have explicit installation instructions for each product type – lap siding, plank siding, vertical sheets, soffits, trim, shingle siding and etc.. James Hardie,, has a very good web site with downloadable instructions, diagrams, estimating tips, and product information.

Fastening the materials to the walls can be accomplished by two different methods.

o Blind Nailing – which is the action of placing a fastener through the top edge of lap siding that will be covered by the next course or lap.

o Face Nailing – which is the action of placing a fastener through the overlap of a plank. The fasteners will be visible.

In conjunction with ICC Evaluation Service, Inc. an extensive technical document was published in 2004 regarding cement fiber products. The report is entitled ICC ES Legacy Report NER-405, which contains test results of wind speeds, nailing techniques, thermal qualities, permeance values, loading, and other extensive technical engineering results and findings. This manual can be found at James Hardie website.

Green Products

These products are considered environmentally friendly since there are no detrimental affects on the environment. Use of these types of products eliminates wide spread clearing of our forests for building purposes. The products are durable with a long life expectancy and do not need to be continually replaced during the typical ownership or life cycle of the building. The raw materials that are used to produce the products are low in toxicity wood pulp, sand, cement, and water and are recycled up to four times. Additionally, Hardie produces a Unique Color Plus manufacturing process that bakes on paint in their factories which delivers a quality consistent finish, eliminating VOC’s during the exterior painting process, with a 15 year finish warranty that ensures reduced needs for repainting.