Comparison of siding for homes.

How to Fasten Fiber Cement Siding

by Arlene Miles

Fiber cement siding is durable and easy to maintain. A composite made of Portland cement, silica and wood fiber, it is often used in high-end subdivisions where vinyl siding is prohibited. Professional installation is expensive. Learning how to fasten fiber cement boards to the exterior of your house will save approximately half of the overall cost.

Tools and Accessories

Although you can attach fiber cement siding by hand, using a pneumatic nail gun will make the job easier and quicker. Rent one as this tool is expensive for do-it-yourselfers. Make sure you have a nailing gun specifically designed for attaching cement siding as framing nailers will over drive nails. Set the nailer to 80 to 85 psi. If you choose to hand nail, use a smooth-faced hammer. Other tools include a nail placement adapter, a variety of gauges for alignment, H-covers and H-channel and off-stud joiners.

Wall Preparation

Sheath walls of new construction with half-inch plywood before attaching fiber cement siding. On existing homes, remove all trim and flashing and lap siding if also present. Place tar paper over the exterior surface. Install new flashing before attaching siding. Layout is the same as for wood or vinyl siding starting at the bottom of each wall. Install a starter strip at the bottom. Mark stud locations on the soffit and foundation areas not covered by tar paper. Follow stud location marks and snap chalk lines to guide nailing and placement of siding joints.

Nailing Basics

Every fiber cement manufacturer has specific instructions, but here are some basic rules. Use 6d or 8d galvanized or stainless siding nails. Install one nail approximately 1 inch below the top edge of the plank over each underlying stud at a maximum width of 16 inches. Nails should penetrate at least 1 1/4 inches. Never drive nails in at an angle. The nail head should sit on the siding surface, because if it is countersunk, siding won’t hold as well. Drill pilot holes for the first few nails in each plank, especially when nailing by hand, to avoid cracking the boards. Also check your town’s building codes to make sure you comply with local structural requirements.

Fastening to Metal

When attaching cement board to metal framing, use self-tapping, corrosive-resistant, ribbed bugle-head screws specifically made for use with fiber cement siding. Corrosion-resistant pneumatic pins are also acceptable. Consult the pin manufacturer for specific instructions.

Alternative Wall Attachment

Fastening siding for non-vertical walls and alternative wall systems, such as structural insulated panels, insulated concrete forms and rain screen systems, has different requirements. Attach fiber cement siding on walls that are no more than 30 degrees from vertical or no less than a 60-degree angle when measured from the plane of the ground. Install a waterproofing membrane on these surfaces before attaching fiber cement siding. Check manufacturer recommendations and local codes for additional fastening requirements over alternative wall surfaces.

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