Understand the ground.
Manage the risk.
Deliver outcomes that endure.

Practical Solutions

Clear, constructable geotechnical advice that works on the ground.

Regional Focus

High-quality consulting for regional NSW — councils, contractors and private clients.

Accountable Engineers

Our engineers own their work and stand behind every recommendation they make.

Geotechnical expertise across three markets

We work with local government councils, civil contractors and private developers — each with different needs, timelines and expectations. Find your sector below

Local Government Infrastructure Geotechnical Services

We are dedicated to providing high-quality, value-for-money geotechnical consulting to local government infrastructure projects across regional NSW.

    • Planning and execution of geotechnical investigation programmes

    • Desktop review

    • Site reconnaissance

    • Drilling, sampling, in-situ testing and laboratory analysis

    • Clear geotechnical models, design parameters and risk identification

    • Geotechnical investigation and foundation design for bridge replacements, upgrades and new crossings

    • Preliminary assessment

    • Intrusive investigation, drilling, foundation selection and detailed design

    • Extensive experience with council and state-funded bridge programmes across regional NSW

    • Timber bridge replacement

    • Load-limited structures

    • Flood-damaged crossings

    • Full-service pavement investigation programmes for councils managing ageing road networks

    • DCP testing, pavement coring, sampling and laboratory analysis

    • Long-term rehabilitation designs

    • Geotechnical investigation for trunk mains, pump stations, rising mains and reticulation upgrades

    • Subsurface data for geotechnical risk and water infrastructure design

    • Specialist geotechnical assessment for horizontal directional drilling (HDD) and other trenchless pipeline crossings

    • Subsurface geology characterisation

    • Mixed-face drilling risk identification

    • Geotechnical data report preparation

    • Investigation, risk assessment and remediation design for slope instability, landslides and geohazard-affected infrastructure

    • Practical, staged remediation recommendations e.g. drainage, retaining structures, toe works and rock stabilisation

    • Comprehensive geotechnical design services covering foundation systems, retaining structures, earthworks and ground improvement

    • Clear, constructable designs using site investigation data

    • TfNSW-accredited slope risk assessors

    • Systematic inspection, risk scoring and prioritisation of road slopes in accordance with the TfNSW Slope Risk Rating System

    • Geotechnical investigation and pavement assessment for regional airports

    • Runway rehabilitation, taxiway upgrades and apron construction

    • NASF-compliant geotechnical programme experience

Construction Phase Geotechnical Support

When the excavation opens and conditions don't match the drawings, you need a geotechnical engineer on the phone — or on site — fast. We provide responsive, senior-level construction support that keeps your project on track.

  • On-site supervision of bored piles, screw piles and driven piles — confirming founding conditions, rock socket depth and pile set against the design assumptions. We provide real-time advice and same-day reporting to keep your programme moving.

  • Visual and technical inspection of excavated footing bases, pad foundations, strip footings and raft slabs — confirming bearing material and reporting against the geotechnical design parameters prior to pour.

  • Proof rolling of prepared subgrades and fill platforms to identify soft spots and delineate areas requiring treatment prior to pavement or slab construction. We provide clear pass/fail guidance and remediation advice on the day.

  • Assessment of exposed founding materials — rock quality, weathering profile, defects and bearing capacity — to confirm suitability against design assumptions or advise on revised founding levels.

  • Design and assessment of working platforms for piling rigs and heavy plant operating on soft ground — ensuring safe and stable working conditions without over-designing the platform at the cost of programme efficiency.

  • Ground-condition-specific advice on excavation methodology, dewatering strategy, temporary works and construction sequencing — from the people who investigated the site and understand what's actually in the ground.

  • Classification of excavated soils and fill material as Excavated Natural Material (ENM), Virgin Excavated Natural Material (VENM) or regulated waste — providing the documentation your project needs for legal disposal, reuse or transport of excavated material in NSW.

Geotechnical Services for Private Development

Whether you're a developer progressing a rural subdivision, a builder needing a soil test before laying a slab, or an owner needing a wastewater report for your DA — we provide fast, practical and council-ready geotechnical reports across regional NSW.

  • Development applications across NSW increasingly require a geotechnical investigation report — particularly for sloping sites, flood-affected land, acid sulfate soils areas and rural lots. We scope and deliver the geotechnical reports councils need, without unnecessary delay or overreach.

  • Before you lay a slab, you need to know what you're building on. We conduct soil testing and AS 2870 site classifications for residential lots, dual occupancies and subdivision stages — fast turnaround, clear reports, builder-ready output.

  • Rural and semi-rural blocks require a wastewater assessment — also called an On-Site Sewage Management System (OSSMS) report or land capability assessment for sewage management — before council will approve your DA. We assess soil permeability, site constraints and effluent disposal options and prepare the full report your council needs.

  • Residential and rural subdivision requires a coordinated package of geotechnical reporting to satisfy council conditions — soil classification, land capability, slope assessment, acid sulfate soils and construction suitability. We deliver everything your DA package needs.

  • Steep or irregular sites require careful geotechnical assessment before you can design. We assess slope stability, identify landslide and geohazard risks, and provide retaining wall recommendations — turning challenging sites into approvable, buildable assets.

  • If your development site has a history of industrial, agricultural or potentially contaminating land use, councils and certifiers may require a Preliminary Site Contamination Assessment (Phase 1 ESA) before approving your DA. We prepare desktop-based Phase 1 assessments identifying potential contamination risks and recommending next steps. Where intrusive investigation is required, we also deliver Phase 2 Detailed Site Investigations (DSI) — so you can progress your approvals with confidence.

  • We provide geotechnical investigation and design services for commercial, industrial and large-scale residential development — including foundation design, earthworks assessment, pavement design, and construction phase support from the same team that investigated the site.

Need a quote for your development?

Tell us your site address, proposed development type and what reports you need — we'll come back to you with a clear scope and fee, usually within 24 hours. Areas we service:

Mid North Coast

Hunter Valley

New England

Northern Rivers

Mid Coast

North Coast

Western NSW

Southern Highlands

Port Macquarie

Coffs Harbour

Tamworth

Armidale

Grafton

Taree

Kempsey

Lismore

Byron Bay

Mudgee

Mid North Coast • Hunter Valley • New England • Northern Rivers • Mid Coast • North Coast • Western NSW • Southern Highlands • Port Macquarie • Coffs Harbour • Tamworth • Armidale • Grafton • Taree • Kempsey • Lismore • Byron Bay • Mudgee •

Geotechnical consulting built on expertise, trust and transparency.

  • Senior engineers on every project

  • Deep regional knowledge

  • Responsive and reliable delivery

  • Practical, proportionate advice

  • High-quality, defensible reporting

  • Independent and transparent

Let’s talk about your project

Phone: 0477 220 099

Email: dan.soffer@collinswilliams.com.au