How to Build Rail Footbridges

Measure the distance from one side of the shore to the other, over the stream or crevice. Stand at least 3 feet from the crevice and measure, as you'll need the bridge supports to be positioned on dry, level ground before the decline of the slope. Measure your desired bridge width. Although width is a matter of preference, at least 3 feet is recommended for comfortable walking room. If you find the distance between shores more than 20 feet, you need something larger than a footbridge to be built.

Mark your measurements by hammering stakes into the ground. Jot down your resulting measurements and use the numbers as a reference when you purchase your building materials. Remember to add 3 feet to each end of the bridge length for 6 additional feet for support purposes.

Use a point-end shovel to prepare a pair of leveled-off areas on flat ground, on either side of the bridge, for the placement of the wooden pier blocks. A total of four spots are needed. Dig 2 to 3 inches deep and use a level to ensure the ground is even and level. If needed, add hard-packed fill dirt to make the areas even with one another.

Run one of the wooden 4-by-4 beams across the crevice, from one pier block to the opposite block across the way. Hammer four or five 16-penny nails through the block and into the beam to secure the beam in place. Repeat for the other blocks to complete the framework for the footbridge.

Saw the 2-by-4s to match the width of the bridge, but remember to add 4 inches to each side so that the ends of each 2-by-4 will rest neatly over the 4-by-4s. Position each 2-by-4 perpendicularly over the supports with their edges flush to one another and screw their ends into the support beams. You now should have the completed footbridge.

Use posthole diggers to dig 2-foot-deep holes on the outsides of each pier block. Stand each 6-foot-tall 4-by-4 into each hole and place a level across the top of the beam to ensure each beam is re level. Fill each hole around the post halfway with gravel and sand; fill the remainder of the hole with fill dirt. You should now have four vertical support beams.

Hammer or screw 2-by-4s horizontally over the tops of these beams to add secure railing. If desired, paint, stain, clear coat or use water sealant to treat the wood. That will protect the footbridge from the elements and prolong the life of the bridge.