By Paul Bianchina
If you're considering your options for siding your new home or residing an existing one, don't overlook fiber cement siding products. One of the relatively new generation of engineered composite-material products, fiber cement siding is both attractive and extremely stable and durable.
Fiber cement siding is manufactured from a combination of cellulose fiber material, portland cement and silica sand, along with water and other additives. And unlike earlier generations of somewhat similar products, today's fiber cement products contain no asbestos. Fiber cement siding is an especially good product for use in areas that are subject to high winds, and its high fire resistance makes it a great choice in wooded areas where wildfires are a concern. It's also an excellent product for use in high-moisture areas where warpage or termite damage would shorten the life of wood or wood-composite siding.
The wet fiber/cement/sand mixture is formed into siding sheets that match many standard plywood siding patterns, or into individual boards for use as horizontal lap siding. Both types of siding are available with a smooth face or a face that is embossed to resemble actual wood siding boards such as natural milled or milled and cross-sawn cedar. Pattern repeats are widely spaced, so the installed siding has a natural wood look to it after it's painted.
After the forming process, the siding material is autoclaved - a process of drying and curing the boards using superheated steam under pressure - so it has a very low moisture content. A low moisture content translates into a material that is very stable after installation - no warpage or excessive movement - and one that promotes excellent paint adhesion.
As with plywood siding, sheet sizes are 4' wide and 8', 9' or 10' long. Board siding is available in 9 ˝" and 12" width and in 14' lengths instead of the 16' found in most composite wood siding products. Weight is a minor concern with fiber cement products - a fiber cement siding sheet or board weighs about half again as much as a comparable size composite wood sheet or board.
Fiber cement siding products are installed in much the same manner as wood siding. Over wood framing you can fasten the siding using hand- or air-driven galvanized nails or wood screws, or use self-tapping screws for installation over metal studs. The siding is compatible with most other types of material now on the market, so you can utilize any type of natural wood or composite wood product for corner boards and trim. Most manufacturers also offer metal inside and outside corner pieces and metal splice connectors for butt joints on long walls, all available with a smooth or wood-textured surface to match the type of siding you're using.
Cutting fiber cement siding products is a little more tedious and time-consuming than working with natural wood or composite wood siding. Most manufacturers recommend first scoring the face side of the material about one-third of the way through, using a special tungsten carbide-tipped scoring knife. A straightedge is then placed along the score line, and the board is snapped upward along the score. There are also special shears known as guillotine cutters that can be purchased and sometimes rented where you purchase your siding - a worthwhile option that greatly speeds up the cutting process. There are also certain types of tungsten-tipped circular saw and jigsaw blades available that will work with these products.
When cutting and nailing, follow the manufacturer's specific instructions carefully, both for your own safety and to ensure warranty coverage in the future. Remember that cutting this product - especially with power saws - produces a fine dust with microscopic fibers in it, so it's imperative that you wear both a respirator and goggles.
Fiber cement siding products and optional components such as metal corners are available through most home centers and lumber yards, either in stock or by a quick special order.
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