Key takeaways
- Clay soil swells when wet and shrinks when dry
- Uneven movement is a leading cause of cracked slabs
- A compacted gravel base evens out support
- Good drainage keeps soil moisture steady
If your yard has heavy clay, your concrete is sitting on soil that moves.
What clay does
Wet clay swells and dry clay shrinks, and the movement is rarely even across a slab. That pushes and pulls the concrete, and cracks follow.
What helps
A properly compacted gravel base gives a stable, even layer between the clay and the slab. Removing soft or organic soil first helps too.
Keep the water steady
Slopes, gutters and downspout extensions that move water away from slabs keep soil moisture from swinging. Drainage is part of the concrete job.
Expect some movement
No slab is crack-proof. Joints, steel and a good base keep movement small and in the right places.
Related
Questions about your own project? Call or text 720-295-9670, or use the estimate form below.