Wind, Storms and What a Fence Can Honestly Withstand

The Columbus area knows severe weather. The tornado outbreak of March 3, 2019 produced an EF4 tornado that moved through the Beauregard and Smiths Station area of Lee County, Alabama, on the western side of this metro, and killed 23 people. Smiths Station functions largely as a bedroom community for Columbus and Phenix City.

It is worth being honest about that up front, because it sets the frame for a conversation the fencing industry sometimes handles badly.

What no fence can do

No residential fence is a tornado-resistant structure. Nobody should sell one as such, and any marketing that implies otherwise should be treated with suspicion. A fence is a light structure at the edge of a property and it is not designed to resist that kind of event.

What good fence construction genuinely affects is ordinary severe weather, which is vastly more common and does far more cumulative damage: thunderstorm gusts, straight-line winds, and limbs coming down out of the tree canopy that covers so much of this area.

Wind load is about surface, not height

The single most useful thing to understand is that a fence resists wind in proportion to how solid it is. Wind pushes on surface area, and that force goes into the posts and their footings.

A six foot solid privacy panel presents a full, unbroken face to the wind. A six foot chain link or spaced-picket fence at exactly the same height presents very little, because the air goes through it. Same height, same posts on paper, radically different loads in practice.

This is why the most common wind failure is a run of solid privacy fence going over as a unit, taking the posts with it, while the picket fence next door is untouched.

Semi-privacy is the useful middle

For homeowners who want the screening of a privacy fence but worry about wind, there is a genuine engineering answer and it does not cost more.

Shadowbox, sometimes called good-neighbor, alternates pickets on either side of the rails. From straight on it blocks the view. At the picket gaps, air passes through. It looks the same from both sides, which is a separate advantage on a shared line.

Spaced picket with a wider board, where pickets are set with a deliberate small gap rather than butted, does something similar with a different look.

Both cost roughly what stockade costs and both behave meaningfully better in a gust. The trade is that privacy at an oblique angle is reduced, which some people mind and most do not.

What holds a fence down

If a solid privacy fence is what you want, the wind resistance is all in the ground.

• Bigger holes. A wider concrete collar resists overturning better than a narrow one, and a hole roughly three times the post width is the working standard.
• Deeper posts. About a third of post length below grade, and more for solid panel at height.
• Closer post spacing. Six feet between posts instead of eight is a meaningful increase in the number of posts sharing the load, and it costs less than people expect.
• Real gate hardware. Gates catch wind like sails and slam. Heavy hinges and a positive latch stop a gate from destroying itself and its post over a season.

Limbs, which cause more damage than wind

Across the wooded parts of Muscogee and Harris counties, the most common cause of fence damage is not wind acting on the fence at all. It is something falling on it.

There is not much construction can do about a large limb. What construction can do is determine whether the repair is a section or the whole run. A fence built in discrete panels between posts, with rails fastened rather than continuous, allows a damaged section to be rebuilt in place. Vinyl has a useful property here: rails can pop out of routed posts under extreme load and be reseated, where a wood rail would have snapped.

The other practical measure is not a fence measure. Looking up at what overhangs the fence line before building, and dealing with obviously compromised limbs, prevents more damage than any specification does.

After a storm

Photograph damage before anything is moved, because that is what an insurance conversation will need. Fences typically sit under the other-structures portion of a homeowners policy rather than the dwelling coverage, and that portion is generally a percentage of the dwelling limit. Whether a specific claim pays depends on the cause of loss, the deductible and the policy wording, and the insurer is the only party who can answer it.

Then get an honest look at whether it is a repair or a replacement. A young fence with one damaged section is straightforwardly worth fixing. A fifteen year old fence that lost a section and has three posts moving at the soil line is telling you something different. The repair page covers what can be fixed without taking down the run.