Fiber-cement siding has been around a long time. The first house I worked on in the late 1940s was covered with fiber- cement siding. It was a bit brittle but just about indestruc- tible. It fell out of favor because it was hard to work with and full of asbestos, whereas high-quality wood siding was inexpensive and becoming widely available.
Times have changed. Today, wood siding is expensive and often lacking in quality. Modern fiber-cement siding, on the other hand, contains no asbestos and offers all of its old ad- vantages and a few new ones, too. I like it because it is simple to install, holds paint well, is fire resistant, is easy to trim out, and won’t decay, rust, or mold. And if that wasn’t enough, it has a 50-year guarantee! Like vinyl, it’s fairly easy to work with, thanks to the new cutting and nailing equipment avail- able today. Unlike wood, it doesn’t cup, curl, or attract ter- mites. Unlike vinyl, it doesn’t burn, melt, expand, or contract.
Once you learn a few basic techniques, such as how to cut and nail it, fiber-cement siding is easy to install and goes on one plank at a time. The siding can sometimes be nailed directly to studs that have been covered with housewrap. In high wind and earthquake areas, siding often has to be nailed on walls that have been sheathed with OSB panels. These
OSB panels add lateral and structural strength to a building. In such cases, care must be taken to insure that moisture passing through the walls does not settle on the OSB and cause rot. This problem can be dealt with by creating a space between the siding and the OSB. There are different ways to create this buffer zone. To learn how to approach this part of the project, refer to the manufacturer’s product and installa- tion information, which is comprehensive and extremely use- ful (see Resources on p. 279).
Fiber-cement clapboard siding comes in various widths that are usually 12 ft. long and 5⁄16 in. thick. Both smooth and wood-grain textures are available. For best results, order the siding pre-primed on both sides. You can also purchase 4-ft. by 8-ft. panels that have vertical grooves like T1-11, or smaller panels that have a shingle pattern. For best results, order the siding pre-primed or with a permanent color already on the siding. After it has been delivered to the job site, keep it covered with a tarp whenever you’re not using it to mini- mize moisture absorption. Store the siding flat and level, too, so it doesn’t break or warp.
Cutting tips
Fiber-cement siding can be cut with a regular circular saw and a conventional carbide blade, but a diamond-tipped ma- sonry blade with four to six teeth works much better and is probably cheaper in the long run. The biggest problem with
Space can be created between the wall sheathing and the siding either by using a rain screen or by nailing lath strips to each stud. This space allows moisture to drain and protects wood from rot or mold. [Photo by Don Charles Blom]
Layout to set the levels for horizontal siding can be done with a story pole. Use the story pole to mark the siding layout on doors, windows, and trim all around the house. [Photo by Don Charles Blom]
CLOSING IN 151
cutting fiber-cement with a power saw is that it creates a lot of dust. Be sure to wear a good dust mask and follow the manufacturer’s recommendations to avoid unnecessary ex- posure to silica, which can damage your lungs.
I prefer to use a set of electric fiber-cement siding shears, a power tool designed specifically for this job (see Resources on p. 279). The shears cut cleanly, don’t create any dust, and can be used for both straight and curved cuts. For small holes, such as those for exterior electrical outlets, use a jigsaw with a carbide-tipped blade. Cut round holes for pipes with a carbide- tipped hole saw mounted in a heavy-duty, two-handled drill.
Corrosion-resistant fasteners
Most companies guarantee their fiber-cement siding for 50 years. Therefore, it will last a long time—provided it’s properly attached with high-quality, corrosion-resistant nails. I generally use regular 2-in.-long, hot-dipped galva- nized nails. If I’m working near the ocean or another area with high humidity, I often use stainless-steel nails.
For the most part, builders use pneumatic nailers to at- tach fiber-cement siding to walls. I’ve found that a regular pneumatic nailer works better than a roofing nailer (see Resources on p. 279). Make sure that the pressure is set correctly once you get started so that you don’t overdrive the nails. Nailguns these days often have a depth gauge to ensure that nails are driven flush with the surface. And there are special coil nailguns that have been developed specifically for siding. Fiber-cement siding can be nailed by hand, but you may need to predrill the nail holes to keep from breaking off the end of the plank. It’s a good idea to have a pocket full of felt strips (3 in. by 8 in.). Each time you have two pieces of siding meet at a butt joint, slip a piece of felt behind the joint and let it lap down on the lower course about an inch. This will help prevent water from entering at the joint.
Trim details
As with wood siding, trim for fiber-cement siding is usually installed first, and then the siding panels are butted against
it. Fiber-cement trim is available for inside and outside corners, doors, and windows, as well as for covering fascia boards and soffits. The illustrations on p. 152 show a few of the trim details available. These same details also work for wood clapboards and wood shingle siding. The trim should be fairly thick—either 5/4 (11⁄4 in. thick) or 2×—in order to stand proud and cover the ends of the siding.
At the outside corners, the siding can butt against the cor- ner boards or be covered with aluminum corner pieces (called siding corners). These pieces have been used for many years as trim for wood siding and work just as well with fiber-cement siding. The siding is installed first and stopped exactly at the corner. After all the siding is in place, the siding corners can be slipped under each course. A flange at the bottom of the corner hooks a row of siding and a 6d or 8d galvanized nail is driven through a hole in the top to hold it in place.
Installing siding panels
The installation details for fiber-cement siding are similar to those for wood clapboards. The bottom-most course of siding rests on a 5⁄16-in.-thick, 11⁄2-in.-wide starter strip cut from the siding or from pressure-treated wood. The bottom edge of the first course should lap about 1 in. below the top of the founda- tion. To install subsequent courses, follow the manufacturer’s recommendations for overlapping and nailing. After you know the amount of reveal the siding will have, you can establish the height of each course. For example, a typical lap on 81⁄4-in.-wide
Siding can be highlighted by using different paint colors. The con- trast adds to the beauty of the building. [Photo by Don Charles Blom]
siding is 11⁄4 in., which leaves a 7-in. reveal. This reveal can be marked on each piece of corner trim and on every door and win- dow all around the house by using a story pole. A reveal can be adjusted up or down slightly (up to 1⁄2 in.) in order to fit siding pieces around door and window openings, and to maintain a uniform distance between the top of the wall and the uppermost siding course. To make sure the last course of siding will be uni-
form in width, measure down from the top of the wall frequently (every other course or so) and fine-tune the reveal, if necessary. You can mix and match siding to add a bit of style to a build- ing. Gable ends can be sheathed with a different type of siding than the walls. T1-11 in the gable end, for example, will contrast with lap siding on the walls. Contrasts can be made even greater by painting the walls a different color than the gable end. Rough or sub-fascia Fascia Drip edge Screened vent Soffit
Frieze board Blind nail
Siding Housewrap Sheathing Roof truss Door trim 1-in.- or 11/4-in.-thick stock is used for the outside corner. 11/2-in. square inside-corner trim piece Wall sheathing Fiber-cement siding
Fiber-cement siding often butts directly to trim pieces.
Cornerboard trim
Leave 1/8 in. gap and apply caulk where the siding butts against the trim.
Blind-nail 1 in. down from the top edge of the siding panel.
Fiber-cement or PT starter strip, 5/16 in. thick and 11/2 in. wide
Housewrap Sheathing Min. 11/4-in.
overlap
6-F
FIBER-CEMENT SIDING CONTINUED
SOFFIT, SIDING, AND FRIEZE-BOARD DETAILS
STARTER COURSE, CORNER,
CLOSING IN 153 Do final sheathing work. To save time, apply foam-
sheathing panels over window and door openings, then make cutouts with a handsaw. [Photo by HFHI/ Will Crocker]
other components, such as vents, electrical out- let covers, and special exterior trim. It’s smart to get an overview of the full range of com- patible products before you order siding. Go online to visit manufacturer’s websites or call to request product information (see Resources on p. 279).
STEP 1 INSTALL THE
REMAINING SHEATHING AND THE ROUGH EXTERIOR TRIM
Straight courses of finish siding and sharp-looking exterior trim depend on good prep work on the sheathing and exterior trim surfaces that will be covered with aluminum cladding. A good deal of wall sheathing will already be done at this stage. Now that finish siding is about to be installed, it’s important to make sure the wall surfaces are flat and free of gaps that will cause dips or irregularities when the vinyl is installed. When installing foam sheathing, you can sheathe right over window and door openings, then use a handsaw to cut out the foam from the opening (see the photo on p. 109).
OSB wall sheathing Fiber cement siding Tar-paper splines protect joints. Window screen repels insects. Moisture can
drain out and air can move upward. #15 tar paper or housewrap 1/4 in. by 2 in. lath furring Rain-screen
Furring strips keep the siding away from the wall. This creates a drainage plane helping to keep both siding and OSB sheathing dry.
Detailing a cement-fiber siding wall
FIBER CEMENT SIDING COMPONENTS AND INSTALLATION DETAILS