The Secret to a Fence That Doesn't Lean
Drive around any Colorado neighborhood, and you'll see leaning, zig-zagging fences. The primary cause of this isn't bad wood—it's bad foundations.
The Freeze-Thaw Cycle
Colorado experiences extreme temperature swings. In the winter, moisture in the soil freezes and expands. In the spring, it thaws and contracts. If a fence post is buried in the active freeze-thaw zone, the expanding ice acts like a hydraulic jack, literally pushing the concrete footing out of the ground. This is called "frost heave."
The Rule of Thumb for Depth
To prevent frost heave, fence posts must be buried deeper than the frost line.
A general construction rule is that 1/3 of the total post length should be underground. For a 6-foot fence, that means using a 9-foot post and burying 3 feet of it.
Concrete: The Right Way
Simply digging a deep hole isn't enough. The post must be secured properly:
Don't Let Contractors Cut Corners
Digging 3-foot holes in Colorado's hard, rocky clay is difficult, exhausting work. Cheap contractors will stop at 18 or 24 inches to save time. Two years later, when your fence is leaning into your neighbor's yard, that "cheap" contractor will be nowhere to be found.