Things You'll Need
1-inch drywall screws
1-1/2-inch drywall screws
HardiePlank is a fiber-cement siding product. The first plank is installed at the bottom of the wall and subsequent planks overlap the previous plank by a minimum of 1 1/4 inches. A jig that holds the current plank so it correctly overlaps the previous plank makes installation easier and faster. You can buy commercial jigs that hold the planks in place, or you can make your own.
Cut two pieces of 1/2-inch-thick plywood to 1 inch wide and 3 inches long. Measure the width of the HardiePlank siding and subtract 1/4 inch to obtain the jig height. Cut a third piece of 1/2-inch-thick plywood to 3 inches wide and as long as the jig height.
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Lay a 1-by-3 piece of 1/2-inch-thick plywood along the 3-inch-wide end of the longer piece with the two 3-inch-wide edges flush. Screw the 1-by-3 piece to the longer piece with two 1-inch drywall screws. This is the bottom end of the jig.
Turn the jig over. Mark the end opposite the 1-by-3 piece at 3/4 inch from the end. Lay the combination square on the piece with one leg against the side and the other leg aligned with the mark. Draw a line across the piece.
Lay the second 1-by-3 piece of 1/2-inch-thick plywood on the opposite end of the longer piece with the 3-inch edge aligned with the line. This leaves it overlapping the end by 1/4 inch. Screw the piece to the jig with two 1-inch drywall screws. This is the top of the jig.
Cut 1-by-2 lumber to 3 inches long. Place the narrow edge against the middle of the jig so it runs from side to side, on the same side as the 1-by-3 piece that overlaps the jig end. Hold the piece in place and screw the jig to the 1-by-2 from the other side using three 1-1/2-inch drywall screws. This piece is the handle.
Make two identical jigs. During installation, a helper can use one jig while you use the other. This ensures both installers set the HardiePlank siding at the same overlap and keep the planks level while installing them.
To use the jig, place the bottom end against the bottom of the previous siding plank with the jig body against the same plank; hold it there. Set the next plank on top of the jig inside the overlap. The body of the jig holds the new plank in place while the overlapping piece prevents it from falling off, and the new plank is held at the correct 1 1/4-inch overlap.
Check the overlap required for your lap siding to avoid improper installation. The 1-1/4-inch plank overlap is typical but does not cover every instance.