Japanese gardens typically employ water, or the impression of water, accompanied by garden bridges to achieve a sense of tranquility in the outdoor spaces. A small Japanese garden bridge should serve as a transition between different areas of the garden. If you don't have a natural stream flowing through your garden, the Japanese garden bridge can span a dry creek bed or small valley, or it simply can serve as a decoration. Pressure-treated lumber works best to keep the bridge from rotting.
Cut two pieces of 2-by-12-inch lumber to the desired length for the Japanese garden bridge. A small bridge is usually 8 to 16 feet long. These boards will serve as the stringers to support the walking surface planks.
Tap a 4-inch-long nail into the top, center point of one of the 2-by-12-inch boards, driving it in only slightly so 2 to 3 inches of it stick out. For a 10-foot bridge, for example, drive the nail in at the board's 5-foot location. Wrap a piece of conduit or bender-board around this center nail, making a curve that ends at the bottom corners of the board ends or within 2 inches of the bottom corners. Mark along the conduit or bender-board with a pencil to mark the top curve for the bridge. Cut out the wood along the curved line with a circular saw or jigsaw. A circular saw can make only short, straight cuts. So using a planer or sandpaper may be necessary to smooth the board to make clean, rounded curves.
Draw a shorter curve along the bottom of the board to mimic the larger top curve, leaving about 10 inches of flat board at each end. Cut out this curve.
Place the cut, curved board on top of the other 2-by-12-inch board you cut. Mark the curved board's outline onto the second board. Cut out the curves from the second board with a circular saw or jigsaw.
Stand the curved boards about 4 feet apart with their top curves facing upward. Measure the distance from one board's outside edge to the other board's outside edge and add 4 inches to find the length needed for the bridge's floor planks. The extra 4 inches allows for 2 inches of overhang on each side of the bridge. Cut several pieces of 2-by-6-inch lumber to this length.
Lay one of the cut 2-by-6-inch boards, or floor planks, across the 2-by-12-inch boards, or stringers, at each end of the bridge. Drive 3-inch-long wood screws through the planks and into the top of the stringers, using two screws at each end of every plank.
Hold measuring tape against the inside of the installed planks, and measure the distance from the bottom to the top of the stringer. Add 4 feet to this measurement to find the length needed for handrail posts. Cut 2-by-4-inch lumber to make four handrail posts that length.
Stand the handrail posts upright at the ends of the bridge against the sides of the installed floor planks. The handrail posts should be on the sides of the floor planks that face the bridge's center. The posts go on the outside of the stringers with the wide sides facing outward. Hold a carpenter's level against the sides of the handrail posts, and adjust the posts to make them straight, or plumb. Drive four evenly spaced 3-inch-long wood screws through the handrail posts and into the stringers.
Cut a notch in each end of one 2-by-6 floor plank that you haven't installed, using a jigsaw to make each notch accommodate a handrail post. Set the notched plank in place over the stringers and against the handrail posts. Drive a 3-inch-long wood screw into each stringer, and drive another screw at an angle into each post. Repeat this process to create and install another notched 2-by-6 floor plank at the handrail posts on the bridge's opposite end.
Lay the remaining 2-by-6 floor planks across the stringers. Drive two 3-inch-long wood screws into each end of every plank, securing the planks in place.
Measure the distance from the outside of one handrail post at one end of the bridge to the outside of the handrail post at the bridge's opposite end. Add 8 inches to this measurement. The result is the length needed for handrails; it leaves 4 inches of overhang at each end. Cut 2-by-4s to make two handrails that length. Lay the handrails on top of the handrail posts. Drive two 3-inch-long wood screws through the handrails and into the top of the posts, securing the handrails in place.
Measure the distance from the outside edge of one handrail post to outside edge of the handrail post at the bridge's other end. Cut two pieces of 1-by-4-inch lumber to make them that measurement. Screw them in place about 4 inches below the top of the handrail posts, using two 2-inch-long wood screws at each end.
Brush a wood sealer or stain on the wood to protect it. Alternatively, brush exterior primer and exterior paint on the wood.
Things You Will Need
- Measuring tape
- 2-by-12-inch lumber
- Nails, 4 inches long
- Conduit or bender-board
- Circular saw (optional)
- Planer or sandpaper (optional)
- 2-by-6-inch lumber
- Wood screws, 3 inches long
- Power drill
- 2-by-4-inch lumber
- Carpenter's level
- 1-by-4-inch lumber
- Wood screws, 2 inches long
- Wood sealer, stain or exterior primer and exterior paint
- Multiple coats of sealer, stain or paint probably are needed for good coverage of the bridge's wood. Allow the wood to dry between coats.
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