When landslide risk may be relevant
A sloping block, embankment, escarpment or proposed excavation does not automatically present an unacceptable landslide hazard. Risk depends on the actual slope geometry, ground profile, water conditions, existing structures and proposed changes to the site.
A council, certifier, structural engineer or designer may request project-specific geotechnical input when site conditions or development works raise slope-related concerns. Requirements vary with the site and the relevant approval authority.
Factors an assessment may consider
Relevant observations can include slope angles, previous ground movement, cracking, erosion, retaining walls, surface drainage, seepage, vegetation, cut-and-fill and potential impacts on nearby property.
Where field investigation or more detailed assessment is required, the scope should match the project and the specific questions being asked. A general guide cannot determine the risk or suitability of an individual property.
- Proposed excavation, building loads or retaining structures
- Existing slope condition, erosion and drainage
- Groundwater, seepage and changes to surface water
- Neighbouring property, structures and access
- Any council, certifier or structural-designer request
Request a site-specific slope assessment
Provide the address, available survey, architectural plans, photographs and the exact wording of any approval or engineering request. Previous reports and information about retaining walls, seepage or historic movement may also help define the assessment.
Sydney Geotechnical's slope stability assessments start from $1,500. The final scope and quotation depend on the actual site, proposed development and assessment requirements.
Common questions
Landslide risk and sloping sites: common questions
Does every sloping block need a landslide risk assessment?+
No. The need for assessment depends on the slope, proposed development, site conditions and any relevant council, certifier or engineering requirements.
Can drainage affect slope stability?+
Surface water, seepage and groundwater can be relevant to slope behaviour, but their significance must be assessed for the individual property.
What is the starting price for a slope stability assessment?+
Sydney Geotechnical's slope stability assessments start from $1,500, with the final quotation dependent on project-specific requirements.
Need Assess my sloping site in Sydney?
Get a scope matched to the project
Send the site address, proposed works, current plans and any request from your builder, engineer, council or certifier. Sydney Geotechnical will review the information and confirm an appropriate scope and fee.
This guide provides general information only and is not a substitute for investigation, engineering advice, footing design or approval advice for a particular property. Project requirements and ground conditions must be assessed site by site.
