If you live in the Greater Houston area, you’re not just building on dirt. You’re building on black soil, also known as black gumbo.
The soil is heavy, expansive, and clay-based. It shifts. Shrinks. Swells with the weather.
So as we move into the heat of late May and early June, know that your fence is about to face a tough seasonal challenge.
This is the time of year that perfectly straight fences begin to “wave” or lean as soon as the Houston sun bakes the ground. Here’s what you need to know about how you can protect your investment.
Why does Houston soil make fences lean?
Black gumbo clay soil is highly reactive to moisture. It acts like a giant sponge.
During our rainy spring months, the clay absorbs water and expands. That puts an enormous amount of pressure on your fence’s concrete footings. These volume changes can exert thousands of pounds of pressure.
When the rain stops and 90-degree days arrive in May, the soil dries out and shrinks. As the clay pulls away from concrete footings, it creates “voids” or “gaps” around the base of your fence posts.
When the soil is no longer tightly packed around concrete, even a light wind can cause a post to lean permanently.
How can I keep my Houston, TX fence as straight as possible?
You can “water” your fence!
It sounds strange. But it works.
If you notice deep cracks forming in the dirt near your fence posts, the soil is dehydrating. By lightly watering the perimeter of your yard during dry spells, you keep the clay hydrated and expanded, ensuring it continues to grip the concrete footings.
You don’t need a swamp.
You just need to prevent the soil from pulling away and leaving the post unsupported.
Does the depth of the post hole matter?
Yes. We follow building code guidelines to make sure footings are deep enough to resist the active zone of soil movement. That way, even when the top layer of soil shifts, the bottom of the post remains anchored in stable ground.
You can’t rely on concrete alone: post depth, footing shape, and drainage all matter. You want a smooth, vertical cylinder of concrete that allows the soil to move up and down against the post without catching it like a hook.
What you don’t want is a giant, mushroom shaped concrete footing. That’s the sign of a bad install for a Houston fence, because it gives expansive clay more surface area to grab. When soil swells, it can actively heave a plug like that right out of the ground.
Get the Install that’s Meant for Houston Soil!
As experienced Houston-area fence builders, we exercise the care and craftsmanship it takes to account for black gumbo soil. With proper maintenance, our fences stand straight year after year, and continue to look great.
Ready for a quote on your custom job? Contact us to get started today!