How to Put Up a Picket Fence If the Ground Is Not Level

Keep the picket tops level to build a fence over uneven ground.

Working on uneven ground is a little trickier and requires setting each picket individually to accommodate the changes in the ground while maintaining a straight top line. There is a simple trick that can help you accomplish this quickly and easily.

1. Mark your fence line with wood stakes and mason's twine. Drive a stake in the ground at each corner and string the twine between the two stakes. Mark the line every 8 feet by wrapping a piece of tape around it; these will be the post positions.

2. Dig the post holes 10 to 12 inches across and 24 inches deep. Cut the posts to length. Picket fence posts typically are 2 to 3 inches shorter than the tops of the pickets, which vary in height. Figure the post length by subtracting 3 inches from your picket height and then adding 24 inches for the hole. Set one cut post in each hole.

3. Attach two, 2x4 runners, one 3 inches above the ground and one 3 inches below the top of the posts, between the first two posts. Use 8 foot treated 2x4s and attach them with 3-inch treated deck screws so that the ends line up with the center of the posts.

4. Work down the line attaching runners. Put the next pair up to the first and repeat the pattern with each new post. Add ½ of an 80-pound bag of concrete in each post hole. Add water to the hole and mix the concrete with a scrap of wood. Follow manufacturer's recommendation for the amount of water for best results. Use a level to check posts front to back. Add dirt to fill the remainder of each hole and pack firmly to hold the post in place as the concrete dries.

5. Screw a scrap piece of lumber to the outside of each corner post extending at least 4 inches above the top of the post. Drive a nail halfway into each scrap on the face that lines up with the front of the fence. Tie the mason's line between these nails to represent the top line of the pickets.

6. Set the first picket in place with its top even with the mason's line. Use a level to make sure that it is straight up and down and attach to the 2x4 rails with two treated deck screws in each rail. Cut a piece of lumber or use a spare picket to space the next picket off of the first. Use the mason's line to position the top of the picket.

7. Cut any pickets that are too long. Measure how far above the mason's line the picket rises and cut that much from the bottom edge of the picket before installing. Continue spacing and installing pickets until you reach the end of the fence.