Anyone planning carport construction will know - or will eventually discover - that setting carport posts is the primary key to the stability and the durability of the carport. No matter how secure your carport roof is, if it is not supported by sturdy, straight posts, there is an increased possibility that your carport could collapse. For this reason you should learn all you can about setting your carport posts. Refer to the information below to learn more about this type of project.
Step 1 - Post Material
You will need to plant a minimum of six posts that will support your carport roof. These will include one at each corner, and two in the center. Knowing which material to use and where to plant your posts are important factors in building a secure carport. For post material, choose one such as pressure treated pine, that will resist rotting and insect damage when it is planted in the ground.
Step 2 - Post Height
The length of your posts will help determine the height of your carport roof. The second factor will be the depth these posts are planted in the ground. Plan for your carport height by buying, or cutting, posts that produce the roof height you desire. A good rule of thumb is to be sure it will be as high as the tallest person or vehicle who plans to use your carport. For a roof six foot five inches your posts should be six feet five inches plus the 24 inches of the post that will be planted. They should be at least 101 inches long. Leave extra length to be sure you have enough. Any excess length will be cut off later.
Step 3 - Post Placement
In planning where to place your posts, measure in from the outer edge of your carport about 24 inches. This mark will be the center of your post hole. Apply this measurement at each of the six post locations, and mark each location. Drive stakes into each of these post locations, then run a taut string around the perimeter and fastened to the stakes. Use a carpenter square to be sure each post is 45 degrees square with the nearest outside post.
Step 4 - Plant Posts
At the mark you made to identify placement of your posts, and without removing the string you've attached as a perimeter, dig six holes that are about 12 inches in diameter and 24 inches deep. Try to avoid leaving loose soil in the bottom of the hole that could later compact and allow the post in it to sink. Into these holes pour enough wet concrete to bring the top level to about two inches below ground surface. Set in your posts while the poured concrete is still wet. Use a level or plumb bob to set the posts plumb.
Step 5 - Trim Planted Posts
When the post concrete has hardened (usually 48 hours) use your measuring tape and measure 77 inches up from each post base. Place a mark here. Cut off the excess post length wherever it exceeds the 77 inches.