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 I am confident they will be long lasting. The boards come pre-painted and the finish is great. I have been keeping a piece of trim board lying in the mud for the past four years and the paint has not started to peel. As the old asbestos siding held paint really well I think the cement board will too. When I built the addition, the cost of the cement board was a third less than cedar clapboard and there would have been the added expense of painting the cedar. Three years after my addition I re-sided another exterior wall of the house and the colors match perfectly. The major drawbacks are that since the boards only come in twelve foot lengths, there are more seams. My friend and contractor scarf cuts the joints, which helps and makes the seams look better than a typical butt joint. The material is very hard and it is difficult to make the joints perfect. I am certain that this siding and trim will last for generations and will not find its way to a landfill for many years to come.
Advantage of Cement Board Siding:
- Durable and dimensionally stable
- Impervious to wood boring insects
- Doesn’t Rot
- Non Combustible
- Material is cheaper than conventional clapboard siding
- Can reduce the cost of homeowners insurance
- Can be cleaned with a hose
- Requires less maintenance than wood clapboard siding
- Comes Pre-painted or primed, with a factory applied baked-on paint
- Paint is less fade resistant than conventional paint
- Saves the cost & trouble of painting
- Excellent paint adherence
- HardiePlank has a 15 year warranty on their paint, the warranty covers labor as well
Negative Aspects of Cement Board Siding:
- More difficult to work with than wood clapboard
- Needs to be installed carefully for it to look its best
- All joints need to be caulked
- Shows more seems than wood siding because maximum length of the siding is 12 ft.
- Siding is brittle if it doesn’t have a solid backing and pieces can be broken