#FoundationFactFriday: What does your foundation sit on?
Foundation Fact: 60% of all homes built on expansive soils suffer from foundation distress.
What are expansive soils? Expansive soils are soils that experience continuous change in volume causing homes or businesses that sit atop these soils to move unevenly and crack. These soils expand when water is added and shrink when they dry out. Foundation settlement is much more common and prevalent than many realize, especially throughout NC and SC. Foundation settlement is a term that no one likes to hear and is an issue that no one hopes to experience. However, if the correct steps are followed and if the proper repairs are provided, then the issue can generally be resolved quickly and permanently, with little to no disturbance to the property for an expense that is less than initially anticipated, and without decreasing the value of the property.
The details are in the dirt. What type of expansive soils are present in North and South Carolina? North Carolina and South Carolina have a diverse geography from sandy beaches to rugged mountains. These states are separated into three physiographic regions: Coastal Plains, Mountains and Piedmont. Each geographic area has a characteristic type of soil. North Carolina alone has over 400 types of soil. General soil types across both states include: clay, loam, rock, sand and shale. Of these soil types two often cause foundation issues:
- Clay soils – Soils that are rich in clay and silt are more likely to cause damage to a foundation. Clay absorbs water easily, and as it becomes more saturated it expands causing foundations to shift, heave and crack. When clay soils dry out, shrinkage occur causing cracks and leaving gaps where water from a future storm can penetrate easily and deeply repeating the expansion cycle. Foundation damage is most;y caused by clay-rich soils due to expanding rather than contracting.
- Sandy loam – Loamy soils usually show little change with the increase or decrease of moisture temperature and are relatively very stable. The primary concern with foundations built on this type of soil is erosion. When soils underneath your foundation erode, they may begin to unevenly distribute the active soil layer immediately beneath your home that is sustaining the weight of a foundation and home structure.
Soil gains load-bearing capacity and stability with depth. The active soil zone immediately underneath your home or business is the main area of concern when it comes to foundation issues. As you go down, layers of other soil types, such as sand, silt, clay, and loam can be found and deeper below is bedrock composed of rock or densely packed soils.
Carolina Foundation Solutions provides a multitude of applications using various products that can target the deeper layer of earth where densely packed, load-bearing stable soils are ensuring that no future movement occurs. Call us at (877) 770-7050 or fill out this form to schedule a FREE assessment to protect your business investment!