Home / Services / Geotechnical / Hillsborough County, NH
Hillsborough County, New Hampshire
Geotechnical Engineering in Hillsborough County, NH
Subsurface investigations, laboratory soils testing, and geotechnical reporting to characterize site conditions before design and verify them during construction. Hillsborough County is covered on a project basis through our Boston, MA regional hub.
- Dispatched from
- Boston, MA regional hub (48 mi) · project-based staffing
- Lead time
- Scheduled by phone or proposal; lead time confirmed when the scope is set
- Laboratory
- Sugar Land, TX laboratory under chain of custody, or a mobile laboratory for large projects
- Reporting
- Reviewed and issued under a documented quality system; formatted for owner, engineer, and building-official review
- Serving
- Hillsborough County, NH — Manchester, Nashua, Concord
- Coverage
- New Hampshire statewide · 27 regional hubs
- Technicians
- ACI- and NICET-certified field staff; licensed professionals in New Hampshire
- Call us
- (346) 420-5425
Scope
Geotechnical services in Hillsborough County
- Soil borings and sampling programs sized to the structure and site
- Laboratory index testing: Atterberg limits (ASTM D4318), moisture content (ASTM D2216)
- Moisture-density relationships and bearing evaluation for foundations and pavements
- Expansive-soil characterization for slab and pavement design
- Construction-phase verification: proof rolls, subgrade acceptance, fill placement observation
ASTM D4318ASTM D2216ASTM D698ASTM D1557
Full scope, standards list, and pricing basis: Geotechnical Engineering.
Local conditions
Geotechnical conditions in Hillsborough County
New Hampshire's glacial history left Hillsborough County with a highly variable subsurface — dense glacial till overlying bedrock sits alongside pockets of loose outwash sands and, in lower-lying areas, organic deposits that can compress significantly under load. Freeze-thaw cycles are severe, and frost penetration depths demand that foundations be designed with reliable bearing data rather than assumptions. Before design begins and again during earthwork and foundation construction, that data has to come from a structured investigation. We provide subsurface investigations — test borings, test pits, and in-situ testing — followed by laboratory soils analysis and geotechnical engineering reports that give your design team actionable bearing capacity values, settlement estimates, and frost-depth guidance. During construction, we dispatch field technicians to verify that actual conditions match design assumptions. Coverage for Hillsborough County is coordinated through our Boston regional hub.
Glacially deposited soils in southern New Hampshire are known for abrupt lateral variability, meaning subsurface conditions can shift meaningfully within short horizontal distances — a factor that directly influences boring layout and spacing decisions. New Hampshire's frost depth, which can exceed four feet in some winters, is a primary driver of foundation design and makes accurate subsurface characterization essential for any structure with a conventional spread or continuous footing.
FAQ · Hillsborough County
What in-situ field tests do you perform during a boring program in Hillsborough County, and what ASTM standards govern them?
The standard penetration test (SPT), performed in accordance with ASTM D1586, is the primary in-situ test conducted within soil borings. It produces blow-count data used to estimate relative density, consistency, and bearing capacity. Where softer cohesive soils are encountered, we may also collect undisturbed Shelby tube samples per ASTM D1587 for laboratory strength testing. Rock quality designation (RQD) is recorded when borings advance into bedrock.
How does New Hampshire's frost depth affect foundation recommendations in your geotechnical report?
Frost penetration in Hillsborough County can be substantial in cold winters. Our geotechnical report addresses this by recommending minimum foundation embedment depths adequate to keep bearing soils below the frost line, consistent with IBC Section 1809.5 requirements for frost protection. Bearing capacity values and settlement estimates are then tied to those embedment depths so the structural engineer of record can size footings with confidence.
We encountered what looks like organic material during excavation — can your lab quantify how much organic content is present?
Yes. Organic content is measured in the laboratory using ASTM D2974, which determines the loss-on-ignition percentage of a soil sample. Organic-rich soils are problematic for bearing because they compress under sustained load and can degrade over time. If organics exceed acceptable thresholds, the report will recommend over-excavation and replacement, surcharging, or alternative foundation systems appropriate to the site conditions.
Which office covers geotechnical in Hillsborough County, NH?
Field work in Hillsborough County is dispatched through the Boston, MA regional hub, about 48 miles away. Laboratory testing is performed in Sugar Land, TX under chain of custody, or in a mobile laboratory mobilized to large Hillsborough County projects.
Are the technicians you send to Hillsborough County certified?
Field sampling and testing in Hillsborough County are performed by our ACI- and NICET-certified technicians. Geotechnical engineering and professional services are delivered with professionals licensed in New Hampshire, coordinated under one proposal.
Scheduling & proposals
Need geotechnical engineering in Hillsborough County?
Call to schedule a technician, or send project documents for a written proposal.