Yes, a geotechnical report is the primary tool used to determine the necessary depth for piers. It provides a technical roadmap of the subsurface conditions, allowing engineers to calculate exactly how deep a pier must go to reach stable ground.

According to the provided content, the report helps determine pier depth through the following data points:

• Soil Bearing Capacity: The report measures the allowable bearing pressure (in pounds per square foot), which dictates the depth of footings and piers needed to support the structure’s weight.
• Depth to Refusal: The investigation identifies the depth of competent load-bearing strata (such as sandstone bedrock). If a report shows "deep refusal," longer helical piers are required to bypass unstable soil.
• Soil Type and Stratification: The report identifies layers of weak or expansive soils, such as clays. Engineers use this to ensure piers are long enough to anchor into stable, non-expansive material below the frost line.
• Groundwater Depth: Measured in feet below the grade, this information influences foundation design and the selection of deep support systems.

Using this precise data ensures the foundation is neither over-engineered nor under-engineered, preventing future settlement and protecting the structural integrity of the home.