Drought, Downpour, and Why Round Rock Foundations Move

The mechanism, in plain English

• The soil under most of this corridor is a shrink-swell clay. It is not inert - it behaves more like a sponge that changes size. Wet, it expands and pushes up. Dry, it contracts and pulls away, taking support out from under the slab edge.
• A house can tolerate a lot of movement if it happens evenly. The damage comes from uneven movement - one corner shaded and watered, another baking in full sun beside a downspout that dumps a roof's worth of water in one place.
• That is why the same drought produces a cracked wall at one house and nothing at the neighbour's. The difference is usually water management, not construction quality.

What actually helps

• Keep moisture steady rather than heavy. A consistent soaker routine around the whole perimeter beats occasional deep watering on one side.
• Get roof water away from the slab. Downspout extensions are the highest-return foundation spending available to most homeowners.
• Fix negative grade. Soil should fall away from the house, not toward it.
• Watch large trees near a corner. A root barrier is far cheaper than piers, and far better than removing a mature tree.
• Document what you see. Photograph cracks with a date. Evidence over several months is worth more than any single opinion.

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