What is Soil Testing?
Prior to building any new structure, performing soil borings is a crucial first step for determining the suitability of underlying soils and how those will affect your foundation. Soils can vary dramatically in support strength, composition and type across all areas of a building plan, and what you see on the top soil is rarely indicative of what exists below. Particularly in the regions surrounding south Georgia and north Florida, soil borings frequently reveal expansive fat clay soils (locally referred to as "pipe clay") with shrink-swell characteristics in response to periods of drought or heavy rain, which if not taken into account during design and construction can result in catastrophic and long-term structural settlement. While some soils can easily withstand heavy loads, others will crumble under the weight of a small house. For these reasons, most building permits require soil borings certified by a geotechnical engineer.
Soil testing is performed by an engineering technician who advances an auger boring into the soil to a specified depth dependent on the building purpose, weight and local topography. (In Leon county, most residential building permits require 4 soil borings to 10' deep each- 1 on each corner of the house). The engineering technician captures samples and labels variances of the soil as it is penetrated, then brings the soil boring samples to their laboratory for review by a professional engineer. The engineer examines the soil and determines whether a typical shallow spread footing foundation should perform satisfactorily or if a specially stiffened foundation is required. Those recommendations are presented in a report along with a detailed profile of the soil borings.