How to Build Support Columns for an Entry Gate

Dig down 30 inches at each of the desired locations of your gateposts with a post hole digger. Pour crushed gravel into the post holes to a depth of 6 inches. Note that this will help water drain away from the bottoms of the posts and prevent rot.

Insert the posts into the holes. Place a level on a vertical side of one of the posts. Move the post as needed until the level indicates the post is plumb. Move the level to an adjacent side of the post and repeat the process. Note that this will ensure the post is perfectly plumb all around. Have a helper hold the post in this position.

Pound two wood stakes into the ground a few feet away from opposite sides of the post with a hammer. The stakes will act as anchoring points for the ends of the lumber used as braces to secure the post. Hold the end of a 2-by-4 board to the side of the post a few feet off the ground. Nail the board to the post with one 16d nail. Nail the other end to one of the stakes. Secure another piece of lumber to the opposite side of the post and to the other stake in the same manner.

Have the helper release the post once the braces are installed. Check the plumb of the post again and make adjustments to the post or braces as necessary.

Pour concrete -- prepared following the directions on the bag -- into the post hole. Tamp the wet concrete when the hole in half full with end of a scrap piece of lumber to expel any air pockets from the mixture. Continue adding concrete, overfilling the hole slightly so that the concrete is slightly higher than the surrounding ground. Note that this will help shed water away from the post.

Check the plumb of the post with the level once the hole has been filled with concrete. Make adjustments as necessary to the post or the braces. Allow the concrete to dry at least 24 to 48 hours before removing the braces and installing your gate hinges.

Repeat the procedure to install the remaining gatepost. When the concrete has dried for 24 to 48 hours, you can attach the latch to the post.