Many homeowners rarely think about the soil in their lawns or yards. As long as the soil can nourish their garden plants (and drain well), they’re good. However, not everyone is lucky enough to have yards with such soil.
Homes built on top of clay-based soils are prone to foundation problems. These soils drain slowly and take a long time to warm up in summer. Also, they dry out and crack in hot weather. All these attributes test even the most resolute gardeners.
Let’s delve into what clay soil is, look at its characteristics, and learn how it affects your home’s foundation.
What Is Clay Soil?
Clay soil is a fine-grained natural soil that forms when humic shale, a type of sedimentary rock, disintegrates. Unlike loam, clay is rich in minerals such as zinc, calcium carbonate, and mica, among others. Their size and mineralogy of clay distinguish it from other fine-grained soils.
Characteristics of Clay Soils
Clay can change its structure, shape, and color. Some of its major attributes include:
- Fine grains: With particles measuring 0.002 mm in diameter, clay particles are some of the smallest among those that make up soil.
- Plasticity: The clay in fine-grained soils develops cellular plasticity when a film of water surrounds its particles. High plasticity can adversely affect structures such as retaining walls.
- Water retention: Clay soils also have mineral particles that swell up in wet conditions. These minerals enable clay soils to hold a lot of water. The excess water can choke tender roots in your yard.
- Highly alkaline: Another characteristic of clay soil is high alkalinity. These conditions can support some insects and plants. However, most creatures thrive in neutral soils with a pH of between three and eight.
- Hard and permanent: When clay gets exposed to heat or fire, it changes from a malleable material to a hard, brittle, and rigid material.
How Prevalent Is Clay Soil?
While clay soil occurs across the country, it’s prevalent in the South. You will find it on the surface of rocks, riverbeds, and many construction sites. Some parts of Virginia, Maryland, and D.C., where JES Foundation Repair operates, have clay too.
While tilling does break its clumps, it does little to stop the formation of a cohesive mass. This is what helps clay resist plants and stops water from flowing through it.
Clay Soil and Construction
No homeowner likes the thought of having expansive soils like clay in their yard. These soils swell in spring and contract in summer. A slight change in their moisture levels can have drastic effects on a building under construction. What’s worse, clay soils make it difficult for builders to create foundations, driveways, pools, slabs, decks, and other structures.
However, with adequate preparation, it’s possible to pour a slab on clay soils without encountering problems. One way of doing this is excavating soft clay and mixing it with gravel. This creates a stable base for the slab.
Clay Soil Movement
One major characteristic of clay soils is that they swell up when they get wet and reduce in volume in dry weather. This phenomenon is known as shrink-swell and tends to occur on the ground. Homes that are built on shallow foundations are prone to seasonal soil movements, which adversely affect their foundations.
Various factors determine the direction and magnitude of shrink-swell movements. But the major ones are evaporation, compaction, and the presence of below-slab depressions. If clay remains moist throughout the year, its volume won’t change, and soil movements won’t occur.
Clay Soil and Your Foundation
Because clay soils heave and shift, they are likely to instigate structural problems like foundation cracks, which can open up your basement to moisture. Over time, the foundation walls can also bow and buckle. That’s not to mention that clay drains slowly, which can cause water to accumulate behind foundation walls.
It’s possible to waterproof foundations and basements that are built on clay soils. You can eliminate some of the problems associated with clay by installing proper insulation and controlling stormwater.
JES Foundation Repair uses proven underpinning methods such as helical piers and push piers to restore settling foundations to their original levels. To get started, schedule a free foundation inspection and repair quote today.