Phase 1 Assessment

Geotechnical and Contamination Assessments


The desk study and walkover survey are the most cost-effective parts of the site investigation process; they provide large quantities of information at minimal cost.

A desk study is a review of information sources such as historical and geological maps, aerial photographs and environmental databases, which can give indicators about potential site characteristics that may influence a development. These are often carried out prior to purchase of a site and prior to intrusive investigation. The content and focus of these studies will vary from project to project.

The desk study is often supplemented with a walkover survey in order to provide additional information on the geology and likely construction problems. It is also useful to identify any features omitted from the desk study information and to assess access for investigation plant and machinery.

Phase 1 contamination assessments are frequently carried out to clear Planning Conditions or to support Planning Applications to satisfy the requirements of the National Planning Policy Framework (NPPF).

Key issues to assess may include:

  • Phase 1 contamination surveys in accordance with CLR11
  • Historical studies
  • Environmental searches
  • Expected ground conditions
  • Preliminary geotechnical assessments
  • Landslide potential
  • Mining assessments
  • Walkover surveys
  • Intrusive investigation requirements