Cement board siding is a factory-made composite material; Portland Cement, wood fibers and other additives are fused together under extreme pressure. Cement board siding is considered by many experts to be a Green building material because it is extremely durable and made partially from recycled content. CertainTeed, one of the major manufacturers of cement board, claims that its siding contains 30% post industrial recycled content.
Another major manufacturer of cement board siding is the James Hardie Company and their product that simulates clapboard is known as HardiePlank. HardiePlank has become term that most builders use for cement board siding. I used HardiePlank on an addition to my house and am slowly replacing all of my siding with it. I also used trim boards made by the James Hardie Company for the exterior window trim, soffits, fascia, mud boards and corner boards.
I am very pleased with the HardiePlank products and