Chain Link Fence Installation: How Deep Should Posts Be Set?
There are many different opinions on how deep a chain link fence post should be set. While general guidelines can be helpful, residential chain link fencing works best when post depth is based on post function, stability, and ground conditions, not just a single formula.
Understanding the difference between terminal posts and line posts is the key to getting post depth and height right.
Terminal Posts vs. Line Posts
Not all fence posts serve the same purpose in a residential chain link fence system.
Terminal posts are used at fence starts, ends, grade changes, corners, and gate openings. These posts carry the tension of the mesh (fabric), support the top rail with rail ends and brace bands, and hold gate hardware. Terminal posts are also used to break up runs of chain link fabric that are over 100ft long so that the fabric doesn’t sag. Because they handle the most stress, terminal posts must be set deeper and slightly taller.
Line posts are the intermediate posts placed between terminal posts. Their primary role is to support the mesh and hold the top rail in place using loop caps. Line posts carry less weight and tension than terminal posts. Typically, line posts are 1 foot less than the length of the terminal posts.
Recommended Residential Post Heights
For a standard 4-foot residential chain link fence, post heights should differ to allow the framework to be installed correctly. “Above grade” refers to the portion of the post that extends above the ground level, not including the part buried in the soil.
- Terminal posts: approximately 4 ft. 3 in. above grade. These are the stronger posts placed at the ends, corners, or where gates will go—they anchor the fence and hold the top rail.
- Line posts: approximately 3 ft. 9 in. above grade. These posts are installed between the terminal posts to support the chain link fabric along the run of the fence.
This height difference allows the top rail to connect cleanly to the terminal posts while keeping the fence level and secure.
How Deep Should Posts Be Set?
Post depth depends on stability and frost protection rather than a strict formula.
- Posts should always extend below the local frost line, which affects the suggestions below.
- Some soil types, like sandy soil, might need deeper posts as well.
- Terminal posts should be set 6–10 inches deeper than line posts.
- Both post types should be set in concrete.
For most residential applications in most of the United States, line posts are commonly set around 24 to 27 inches deep, with terminal posts set deeper to handle added tension.
Digging the Hole Properly
The shape of the hole plays a major role in long-term stability.
- Hole width should be 3–4 times the post diameter.
The bottom of the hole should be wider than the top (bell-shaped)
- Add a few inches of gravel at the bottom for drainage.
- Crown the concrete slightly so water drains away from the post.
Use a level while the concrete sets to ensure posts remain plumb.
Ready to Start Digging?
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Image Credit: // Shutterstock // albhski
