Also known as Vertisol, expansive soil contains specific types of minerals called smectites, which can absorb a lot of water and expand considerably. The soils containing large amounts of smectites can undergo a 30% volume change according to moisture and temperature variations. A classic example of smectite-rich soil is Houston Black, which can be found in Houston and neighboring cities, including Sugar Land, TX.
If you live in Sugar Land, TX, should you worry about having expansive soil under your home? Not necessarily. Although expansive soil could mean bad news for a Sugar Land homeowner, you can prevent foundation damage by taking a few simple measures. But before we talk about what you can do to avoid foundation problems, let’s take a look at the types of damage expansive soil could cause.
Cracks – Cracks developing in the foundation, slab, floors, and walls are typical problems in a Sugar Land home built on expansive soil. Because this type of soil has a great expansion-contraction capacity, it tends to absorb and retain a lot of water. But it can also shrink significantly when it dries out. Over time, repeated changes in soil volume can exert enough pressure on a foundation to cause cracking as well as other types of damage.
Differential settlement – Expansive soil can lead to differential settlement in one of the two ways:
- When exposed the excess water, expansive soil swells and moves upwards, a phenomenon known as heaving Heaving could also occur during the winter when the soil expands due to the freezing temperatures that penetrate the ground and cause the water to freeze. Heaving could lead to two subsequent problems:
- First, the pressure exerted by the soil against your foundation will force it to move upwards. Once the ice melts and/or the water evaporates, the soil will return to its original state and position. All this movement may cause your home to settle in an uneven fashion.
- Second, overly wet expansive soil usually becomes very soft, with a near-mud consistency. This means that it loses much of its ability to carry the whole weight of your Sugar Land home. In your home, different loads exert pressure on different parts of your foundation. Consequently, one side of your home may begin to sink into the ground more readily than the others.
- During dry spells, expansive soil dries out and shrinks. When this happens, the soil pulls away from concrete structures, while also developing large and deep cracks. As a result, gaps of different sizes may start to appear along and underneath your foundation. Also referred to as soil subsidence, this can remove the support your home needs in order to remain structurally sound over the years.
In all the aforementioned cases, differential settlement is very likely to occur. Since expansion-contraction cycles will place repetitive stress on your foundation, differential settlement may worsen over time. When a foundation moves significantly, the whole structure moves as well. This may cause significant structural damage to the entire home.
Moisture buildup and mold growth –
The cracks that develop in the soil around and under your foundation during dry conditions can facilitate the infiltration of rainwater and snowmelt into deeper soil layers. As a result, excess water that gets under your foundation may create a damp environment in your crawlspace. This could lead to various problems, including musty smell, mold growth, and wood rot. Over time, excess moisture may also affect different structural elements, such as wood studs, and impact your entire floor system, leading to warping, crowning, buckling, cupping, and tiles detaching from the slab.
Tips to Prevent Foundation Damage due to Expansive Soils
Foundation damage can be quite catastrophic for a Sugar Land homeowner. In addition to the fact that foundation repair requires expert knowledge and can be quite expensive, most homeowners insurance policies don’t cover this type of damage. Therefore, many homeowners need to pay for repairs out of their own pocket, even though some of them may qualify for different financing options.
However, you can do a few things to completely prevent or at least mitigate foundation damage from expansive soils since the greatest amount of damage occurs when repeated and significant changes in the soil moisture content; the best course of action would be to maintain constant moisture in the ground around your foundation. This can be done by watering the foundation during dry spells and ensuring proper grading and drainage, limiting water infiltration into the soil during the wet season.
As pointed out, expansive soils aren’t problematic as long as the soil moisture content remains constant around the foundation. Suppose you suspect that repeated soil expansion and contraction cycles have somehow damaged your foundation. In that case, you can contact our foundation repair professionals for a free foundation inspection and estimate. Having your foundation and home thoroughly reviewed by an expert before implementing any preventive or remedial measures will help you correctly address existing foundation damage and prevent future structural problems that may otherwise affect your entire home.