Set the Posts

• Place the fence posts about 6 to 8 feet apart, depending on the wood you are installing and the type of terrain where it will sit. Heavier wood or fences built on uneven ground will need more reinforcement, so the posts should be placed closer together. Dig holes and install the end posts before marking off the locations of the middle posts. Run a piece of twine from one end post to the other and pull it tight so you have a straight edge to use for aligning the other posts. When digging the holes, you can improve the drainage by making the bottom of each hole slightly larger than the top and filling in the gap with gravel. Then set a post into the hole and fill it with quick-setting concrete.
  
  

Install the Rails

• Set a long piece of 2-by-4 inch lumber on top of the fence posts. Each rail should be twice the distance between posts, so you can connect it to a post at both ends and in the middle. If your posts are 6 feet apart, that means you need rails that are 12 feet long. The bottom rails should be about 1 foot higher than the ground, leaving room for the runner that goes along the bottom of the fence. You want the bottom rail to sit above the runner so that you can anchor the pickets. Measure the distance between the posts and cut pieces of 2-by-4 inch lumber to this length to use as the bottom rails. Nail the bottom rails into the sides of the fence posts diagonally or use metal brackets to connect the rails to the posts.
  
  

Add the Pickets

• Place a 12- or 16-foot-long by 1-foot-wide runner board on the ground along the bottom of the fence, in front of the posts. Use a level to make sure it is straight, then nail it into the posts. Repeat this until you have the entire bottom of the fence covered. Rest a fence picket on top of the bottom runner. Be sure it is straight, then nail the picket to the top and bottom rails. Repeat this process until the fence is complete, leaving about 1/4 inch of space between the pickets.