A client recently contracted Howell for engineering services for a potential site for a new headquarters in Whitemarsh Township, PA. A due diligence-level geotechnical investigation was included to ensure the project's feasibility and to identify any subsurface conditions that would add cost implications for design and/or construction.

The subject property was about 22 acres in total with steep slopes and a relatively sharp drop-off in elevation, bisecting the site into upper and lower sections. The proposed headquarters included a ±150,000 SF 2-story office and warehouse building with an underground parking level located on the upper section of the site, and a ±50,000 SF shipping warehouse on the lower section.

Prior to mobilizing our equipment, Howell conducted a desktop study to gain an understanding of the mapped bedrock geology and site history. We learned the lower part of the site was formerly a quarry sometime in the mid-20th century. We developed a boring location plan and completed it over a 4-day span for clearing and drilling operations. With some extra time after clearing the site for drill rig access, our field team completed 4 test pits in the lower and upper portions of the site.

The explorations for the upper portions were unremarkable; however, the lower test pits and borings uncovered a serious cost implication that would contribute to our client terminating the purchase agreement for the property.

Howell concluded the former quarry area had been filled with 30 to 40 feet of undesirable fill materials containing a mixture of soils, debris, and, in some areas, literal bags of garbage. Due to the need for extensive soil improvement, a deep foundation system for the lower warehouse, and required environmental remediation or safeguards, the project became virtually cost-prohibitive.

The important lesson from this case study is the benefit of due diligence. Skipping this phase in your next project to cut costs and boost profits could cost you millions.