Some tips for fiber cement siding installation

Finish: fiber cement has to be painted or stained. This can be done before it's installed—either by the manufacturer or by a paint shop hired by the lumberyard where you order the siding—or after it's up. Manufacturers charge about $1 per square foot and offer a 15-year warranty, but color choice is limited and you get only one coat. Paint shops provide two coats, 25-year warranties, and hundreds of hues for about $2 per square foot, not including the cost to ship your order to and from the lumberyard. On-site painters generally offer one- or two-year warranties on their work.

Trim: For minimal maintenance, use trim made of fiber cement or cellular PVC. Both are rot-proof and come in standard ¾- and 1-inch thicknesses for use as corner, frieze, and fascia boards. Crown moldings are also available. You can also use wood trim with fiber-cement siding. Wherever trim and siding meet, there should be a 1/8-inch gap, concealed with caulk.

Layout: Fiber-cement panels butt together at the edges, making layout a no-brainer. With clapboards and shingles, each course overlaps the next by at least 1¼ inches. The portion that's visible—not overlapped—is called the exposure. (A 6¼-inch-wide clapboard with a 1¼-inch overlap has a 5-inch exposure.) Exposure has to be decided before you order because it determines how wide your siding will be, how much you will need, and how it will look once it's installed.

Installation: Make sure your contractor uses rustproof stainless-steel nails, primes all cuts, and caulks joints with a paintable exterior-grade sealant that will remain flexible. To reduce water absorption, fiber cement has to be installed at least 2 inches above steps, decks, and roofs, and at least 6 inches above grade. Check joints every few years and recaulk as needed.