How to Build a Japanese Garden Bridge

Measure the spot where the bridge will go. If the bridge will be placed over a stream, measure the distance from bank to bank with a tape measure. Use this measurement to determine how long the underlying support beams will have to be to span the stream.

Place two curved, wood beams of adequate length, at least 4 inches to 8 inches wide, on the ground the proper width apart with the arching side up in the air. Make sure the beams run parallel to each other and are as far apart as your bridge will be wide.

Cut each cross plank to length with a circular saw. Place the first cross plank across the width span from beam to beam, lining up the ends of each plank flush with the outer edge of the underlying beams. Screw both ends of the plank down to the beams with four deck screws with an electric screw gun. Repeat this process until you have floored the entire bridge span with cross planks.

Choose a color of stain for your Japanese garden bridge, and apply the stain with an oil paintbrush. Wipe off excess stain material with a rag. Allow the stain to dry.

Add handrails to each side of the bridge. Measure the height from the deck of the bridge, then cut at least six 4-inch-by-4-inch posts for your handrail. Space these upright posts along the outer beam spanning your bridge, placing a minimum of three posts on each side of the bridge.

Drill 1/2-inch holes through the base of each handrail supporting post and through the bridge beams using an electric drill with a 12-inch wood drill bit. Hammer 1/2-inch diameter bolts, at least 12 inches long, through the post and the beam from the outside of the bridge inward. Thread a flat washer and nut onto bolt until tight using a 1/2-inch end wrench.

Screw 2-inch-by-6-inch hand rails to the top of the upright hand rail supporting posts with two 2 1/2-inch deck screws per post. Stain the upright posts and handrails using your oil brush, and clean off excess stain with a rag.