Expansive Clay Soil
One of the biggest contributors to concrete movement in the Dallas–Fort Worth area is expansive clay soil.
Clay-rich soils absorb water and expand during wet conditions. When the soil dries, it contracts and can pull away from or lose support beneath concrete slabs.
This repeated cycle can cause:
- Driveway cracking
- Sunken sidewalks
- Uneven patios
- Raised concrete sections
- Separation between slabs
- Trip hazards
Because moisture conditions can vary across a property, one portion of a concrete slab may move while another remains relatively stable.
Summer Heat and Drought
North Texas summers can bring prolonged periods of extreme heat with very little rainfall.
As moisture evaporates from the soil, expansive clay can shrink considerably. If soil beneath a driveway, patio, or walkway contracts unevenly, portions of the concrete may lose support and begin to settle.
Signs of drought-related concrete movement can include:
- New cracks appearing during summer
- Gaps beneath slab edges
- Sections of concrete becoming uneven
- Soil pulling away from concrete
- Water collecting in newly formed low areas
Extended drought can make existing concrete problems more noticeable.
Heavy Rain After Dry Conditions
North Texas weather can quickly transition from prolonged drought to significant rainfall.
When very dry clay soil suddenly receives large amounts of water, it begins expanding again. This creates upward pressure beneath concrete surfaces.
The repeated transition between dry and saturated soil can contribute to both settlement and heaving.
Good drainage is therefore important not only for foundations but also for driveways, sidewalks, patios, and other concrete surfaces around your property.
Poor Drainage
Water should drain away from concrete surfaces rather than repeatedly collecting beside or underneath them.
Drainage problems can wash away or soften supporting soil beneath concrete slabs.
Common drainage problems include:
- Downspouts discharging onto concrete
- Standing water near driveways
- Poor yard grading
- Irrigation leaks
- Erosion along slab edges
- Clogged or inadequate drainage systems
Over time, erosion can create voids beneath the concrete. Without adequate support, the slab may settle and eventually crack.
Improper Soil Preparation
Concrete performance begins before the concrete is ever poured.
The soil and base material beneath the slab should be properly prepared and compacted. If the underlying material wasn’t sufficiently compacted during construction, it may settle later.
As the base settles, the concrete above can lose support.
This can result in:
- Cracks
- Depressions
- Uneven slabs
- Separation at joints
- Sunken sections
This is one reason newer concrete can sometimes develop significant settlement problems despite appearing properly installed at the surface.
Concrete Shrinkage
Not every concrete crack is caused by soil movement.
Concrete naturally shrinks as moisture leaves the material during the curing process. This can produce small shrinkage cracks.
Proper installation practices—including appropriate concrete mixtures, curing procedures, reinforcement, and control joints—help manage cracking, but they can’t guarantee that concrete will never crack.
Small hairline cracks may be primarily cosmetic, while larger or changing cracks deserve closer attention.
Expansion and Contraction From Temperature Changes
Concrete expands when heated and contracts as temperatures fall.
A North Texas driveway can become extremely hot during summer afternoons and experience considerably cooler temperatures later in the year.
Expansion and control joints provide designated areas where movement can occur. When joints are missing, improperly spaced, or deteriorated, stresses may produce cracking elsewhere in the slab.
Tree Roots
Mature trees can affect concrete in several ways.
Growing roots may place pressure beneath sidewalks, patios, or driveways and gradually lift sections of concrete.
Trees also remove significant amounts of moisture from surrounding soil. During drought conditions, this can contribute to uneven soil shrinkage near large trees.
Homeowners may notice:
- Raised sidewalk sections
- Cracks near mature trees
- Uneven driveway slabs
- Changes concentrated on one side of the property
Heavy Loads
Residential concrete is designed to support normal vehicle traffic, but unusually heavy loads can place additional stress on a driveway.
Heavy trucks, recreational vehicles, construction equipment, dumpsters, or repeated commercial vehicle traffic can contribute to cracking—particularly when the underlying soil or base isn’t providing adequate support.
Damage frequently occurs near slab edges where concrete may be more vulnerable.
