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About This Project
When you want the classic look of wood siding coupled with lifetime durability, fiber cement siding may well be your best choice. Fiber cement siding is a composite made of Portland cement, silica and wood fiber. Once painted, it looks almost identical to wood. It’s available in many styles and widths, both smooth and wood textured, and you still get the crisp joints and details that’ll make your home’s exterior stand out. In addition, it’s highly rot and insect resistant, won’t burn and paints beautifully.
Fiber Cement Is Tougher Than Other Materials
Contrary to expectations, fiber cement is somewhat flexible, not brittle. It installs very much like traditional wood siding with a few easily mastered techniques that we’ll demonstrate in this story. You can hand-nail it, although we recommend you drill 1/8-in. pilot holes. It drills easily with ordinary twist bits and cuts easily too, although with lots of dust. Because ordinary wood-cutting blades dull quickly, we’ll tell you what blades to use. If you’ve ever worked with wood siding, you’ve got the skills and tools to handle fiber cement as well.
Tip
If you don’t have access to a table saw, buy a sheet of 1/2-in. treated plywood and rip furring strips with a circular saw.
We’re also using fiber cement trim boards. Since they’re only 7/16 in. thick, rip 3/8-in. thick strips from treated 2-by lumber and use them to fur out the frieze boards. Now they’ll sit about 1/8 in. above the lap siding.
Cut the frieze board to length. Fiber cement siding is highly abrasive. Even a carbide-tooth blade will last for only part of the day. At home centers, you can buy diamond blades ($48) made specifically for cutting fiber cement. These blades cut quickly and create less dust. But we had success with a less expensive dry-cut, diamond masonry blade ($30). Drill cutouts for electrical boxes and pipes with regular twist bits or spade bits, and make interior or even curved cuts with a jigsaw fitted with a tungsten or carbide grit blade (these blades are available at home centers and tile stores). Cutting fiber cement siding raises a lot of silica dust, so work outside and wear a dust mask.
Nail up the frieze board by drilling 1/8-in. pilot holes and driving two galvanized box nails at each stud. Your nail length may vary from ours depending on the type of exterior sheathing used on your home. In general, use nails that penetrate the studs at least 1 in. Drive the nailheads snug against the fiber cement board. If driven too deep, the heads will crush the fiber cement board and reduce the nail’s holding power. Don’t nail fiber cement corners together. A nail driven into the edge of a fiber cement board will split it.
Tips
Pros use pneumatic coil nailers ($35 per day to rent) designed specifically for fiber cement siding. They cut nailing time in half. If you go this route, practice first to make sure the nailheads will be set flush.
Next make the outside corner, following the same steps as for the frieze boards. Be sure the bottoms of the corner boards cover about 1/2 in. of the foundation.
With the trim boards completed, lay out the siding courses with a story pole. (See “Making a Story Pole,” p. 58.) Hold the top of the story pole snug against the frieze board and mark out the siding courses at all corners and around windows and doors. Following these layout marks, snap horizontal chalk lines. Remember that these layout lines represent the top of each siding course.
Rip and nail up a 3/8-in. thick treated wood starter strip along the bottom of the wall (above the foundation). This strip will tip the first piece of siding to the proper angle. Measure and cut to length the first piece of siding and nail it in place. Leave a 1/8-in. gap where the end meets the corner board and make sure the other end lands on a stud line. Install the next piece so its end butts lightly against the first. Continue with the siding courses, aligning the top edges to the layout chalk lines. Be sure to stagger the butt joints so they don’t lie on top of each other as you work your way up.
Tip
If you drive a nail too deep, caulk over it and then drive another nail next to it.
Making A Story Pole
Cut a straight 1x2 so its length runs from the frieze board to the bottom of the first siding course. Measure up from the bottom of the story pole to mark the full width of the first course of siding (6-1/4 in. in our case). Remember, this mark represents the top of the siding piece, not the bottom of the second course. From this point, make marks up the pole every 5 in. or the recommended exposure for your siding. The top course should be at least two-thirds the width of the lower courses (ours was too narrow, so we decreased the exposure to 4-7/8 in.). When the final layout is OK, draw heavy lines on the face and both edges of the story pole using a square. Now hold the story pole tight against the frieze board at all corners and alongside windows and doors. Transfer the layout marks to the wall and snap chalk lines. This will ensure that all the siding courses go on straight and uniformly.
Notch to go around windows and doors. Be sure to allow a 1/8-in. gap where the siding meets the window trim and sill. This joint will be caulked later. Nail the top edge of the siding along the windowsill at each stud. These nailheads will be exposed, but the paint will cover them.
Tip
If you live in a region of high rainfall or the wall is highly exposed to water, slip a 3-in. wide strip of building paper behind butt joints. Be sure the bottom edge of the paper laps on top of the lower course of siding.
Water intrusion around wall penetrations can be a problem for any type of siding. Lay out and make the cutout for the electrical box. The electrical box cover is gasketed to seal out water. For pipes, electrical entries and similar fixtures, fit the siding as tightly as possible and then seal with a polyurethane caulk or non-hardening electrician’s putty.
Rip the top course of siding to width and nail it up. Hold these nails 1 in. below the top edge. Again, these nailheads will be exposed.
Caulking and Painting
Buy the siding already primed. If you prime it yourself, use an alkali resistant primer. Caulk all the joints with an acrylic latex caulk before applying the final coats of paint. Be sure the caulk fills the 1/8-in. joint completely to keep it watertight. Finish-coat with a 100 percent acrylic latex paint. Then stand back and look. Is it wood or is it fiber cement?
Here are a few major brands of fiber cement siding:
James Hardie: (888) 542-7343. www.jameshardie.com
Cemplank: (877) 236-7526. www.cemplank.com
Certainteed: (800) 233-8990. www.certainteed.com
Suppliers
Most lumberyards and home centers either carry fiber cement siding or can order it for you. Buy it already primed.
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