Phase 2 Site Investigation
We design and deliver Phase 2 intrusive site investigations that characterise ground conditions, quantify contamination risks, and provide the evidence base for remediation strategies. Our investigations follow BS 10175 and the LCRM framework.
Ground truth your site with targeted investigation.
A Phase 2 site investigation follows on from a Phase 1 desk study where potential contamination risks have been identified. We design a sampling strategy based on the Conceptual Site Model, mobilise specialist drilling contractors, and collect soil, groundwater, and ground gas samples for laboratory analysis.
Our reports present analytical results against appropriate assessment criteria (including GACs and SSACLs), update the CSM with measured data, and provide clear recommendations — whether that means the site is suitable for the proposed use or a remediation strategy is required.
From sampling strategy to remediation clarity.
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Investigation design
We design the sampling strategy based on the Phase 1 CSM, targeting identified areas of concern. We specify the number and depth of exploratory holes, sampling frequencies, and analytical suites.
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Fieldwork
We mobilise specialist contractors to excavate trial pits, install boreholes, and collect soil, groundwater, and gas samples. We supervise all fieldwork and maintain chain-of-custody documentation.
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Laboratory analysis
Samples are submitted to UKAS-accredited laboratories for chemical and geotechnical analysis. We specify appropriate analytical suites based on the site history and proposed end use.
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Risk assessment (GQRA)
We assess analytical results against Generic Assessment Criteria (GACs) and site-specific assessment criteria (SSACLs). We update the CSM with measured data and classify contamination risk for each identified pollutant linkage.
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Remediation strategy
Where risks exceed acceptable thresholds, we develop a remediation options appraisal, define a preferred strategy, and outline a verification plan that satisfies the regulator and supports planning condition discharge.
We deliver investigations that close out planning conditions.
- We design targeted investigations that avoid over-sampling and unnecessary cost.
- We use UKAS-accredited laboratories for all analytical work.
- We integrate geotechnical and contamination data to inform foundation design.
- We develop practical remediation strategies that regulators accept.
- We coordinate with our drainage, flood risk, and infiltration testing teams.
Standards we work to
LCRM, BS 10175, BS 5930, and CL:AIRE guidance. Our reports satisfy Environmental Health Officers, the Environment Agency, and building control.
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Frequently asked questions
- What happens in a Phase 2 site investigation?
- A Phase 2 investigation involves intrusive fieldwork — typically trial pits, boreholes, and sampling — to collect soil, groundwater, and ground gas data from the site. Samples are sent to a UKAS-accredited laboratory for analysis, and the results are assessed against regulatory criteria to determine whether contamination poses an unacceptable risk.
- How much does a Phase 2 site investigation cost?
- Costs depend on the number and type of exploratory holes, the analytical suites required, and whether ground gas monitoring visits are needed. A small residential site with a simple sampling strategy will cost significantly less than a large brownfield site with complex contamination. We scope investigations tightly to avoid unnecessary expenditure.
- What is the difference between Phase 1 and Phase 2?
- A Phase 1 desk study is a desktop review that identifies potential contamination risks based on site history and environmental data. A Phase 2 site investigation follows on from the Phase 1 by collecting physical samples from the ground to test whether the identified risks are actually present and at what concentrations.
- What are generic assessment criteria?
- Generic Assessment Criteria (GACs) are published screening values used to assess whether contaminant concentrations in soil or groundwater pose a risk to human health or the environment. Common GAC sets include LQM/CIEH S4ULs and C4SLs. If concentrations exceed these thresholds, site-specific assessment or remediation may be required.
- How long does a Phase 2 investigation take?
- Fieldwork typically takes one to three days depending on the number of exploratory holes. Laboratory results are usually available within two to three weeks, and gas monitoring may require three to six visits over several months. We deliver the final report within two to four weeks of receiving all data.