What Should You Consider When Choosing a Geotechnical Engineer in New Zealand?

The importance of this task makes your choice of geotechnical engineer a critical one. You need to have total confidence that your chosen professional will lay the necessary groundwork for your project, identifying potential issues, ticking all the regulatory boxes, and collaborating effectively with all the other project stakeholders.

You need to choose the right geotechnical engineer. In this guide we'll show you how.

Geotechnical engineering is the study of how earth materials (soil, rock, groundwater, etc.) interact with man-made structures like buildings, roads, bridges and dams.

Geotechnical engineers investigate the geological properties of a site before construction begins. They analyse the soil, bedrock, slopes and groundwater to understand its suitability for the project at hand, and to identify potential hazards and risks. They compile all this information in a geotechnical report, which outlines:

• The geological history and composition of the site.
• The load-bearing capacity of the ground.
• The groundwater conditions and water flow paths.
• The feasibility of the site for the proposed project.

What considerations should you make when choosing a geotechnical engineer? Let's look at the key factors that will influence your decision, and the specific questions you should ask in regard to each.

Qualifications & certifications

At minimum, your engineer will need a bachelor's degree in civil engineering, geology or a similar field. Specialised post-grad qualifications, such as a master's in geotechnical engineering or engineering geology, can indicate a deeper grasp of the field.

It's also wise to choose Chartered Professional Engineer (CPEng), a certification administered by Engineering New Zealand. To achieve CPEng status an engineer needs to demonstrate the ability to handle complex engineering problems and must do so every six years to maintain the credential.

Experience & expertise

Has the engineer previously completed similar work to what you need done? Geotechnical engineering is a long-term game where success is measured over the course of decades, so the best options will bring a deep portfolio of successful projects, featuring projects that are like yours.

There's also huge value in local knowledge. Geotechnical engineering demands a deep understanding of earth materials, which vary dramatically across NZ. The best engineers will bring an understanding of everything from soil types and seismic risks in the local area, and will use this knowledge to inform the work they do.

Services offered

Geotechnical engineering is a multifaceted field. Depending on your project, you might need any combination of the following services:

• Site investigations
• Soil and rock testing
• Slope stability analysis
• Foundation design and assessment
• Earthworks design and monitoring
• Seismic hazard assessments
• Ground improvement solutions
• Retaining wall design
• Infrastructure support
• Erosion and sediment control

The right geotechnical engineer will offer a full complement of services, including those that you may not believe you necessarily need, but that could come in handy if the site presents some surprises.

Reputation & references

Is your chosen firm held in high regard? There are a few ways that you can get a sense of the reputation of a potential geotechnical engineer.

The best is to see what your professional network has to say about an option, as word tends to spread quickly within the NZ construction industry about particularly good or bad experiences.

You can also check the online reputation of a firm, through the ratings and reviews on Google, Facebook, LinkedIn and other relevant platforms.

Ask for case studies relating to projects that are similar to yours. Speak directly to a firm's former clients to gain an understanding of what they're like to work with.

Finally, be appropriately wary of new engineering firms who haven't yet built up a reputation within the industry, and/or can't offer up relevant testimonials and case studies. Geotechnical engineering is focused on long-term outcomes, so it can be more difficult to judge the quality of the work of younger firms.

Cost considerations

Once you've whittled down your options to a few of the best candidates, get quotes for your project.

Pricing for geotechnical services can vary widely from project to project based on several factors, including the scope of work, project complexity, location and accessibility, soil conditions, regulatory and safety considerations, and the testing you require.

But in basic terms, a quote for geotechnical engineering services will be made up of the following elements:

• Site investigation and soil testing: Soil/geotechnical reports, borehole drilling, cone penetration testing.
• Lab testing: Soil classification tests, Atterberg limits/moisture content/grain size analysis, consolidation or shear strength tests.
• Geotechnical consulting and design: Foundation recommendations, slope stability analysis, retaining wall or deep foundation design.
• Specialised testing and services: Seismic hazard analysis, groundwater studies, pile load testing.

Ensure that all your quotes are itemised, so you can compare specific elements.

Often in the construction industry, you pay for what you get. Ensure all options and contingencies are covered in your quote. Be wary of significantly cheaper quotes and double check they contain all the elements needed for your project, otherwise you may be subject to multiple variations that end up costing more than the more pricy quotes.

Communication & project management skills

During the tendering and procurement process you should analyse how each firm conducts itself in terms of communication.

Missed emails, unreturned calls and a general sense of disorder at this early stage may not bode well for the project going forward. This assessment is more qualitative than quantitative - there's a lot to be said for gut feel. If you're not sure a consultant can deliver the goods in terms of communication and project management, that's a good sign that they can't.

There are however specific questions that you can ask to gain an understanding of what an engineering firm will be like to work with:

• If X goes wrong, how would you solve that issue?
• What collaborative tools do you use to track project progress?
• What is an appropriate expectation for response times?

While there are quite a few factors to consider when hiring a geotech professional, there are also a few basic mistakes that can undo all your good work. Examples include:

• Hiring based on price alone: The best geotechnical engineers are rarely the cheapest upfront, but they can be the cheapest in the long run, as they'll ensure your project is built to last. You should be prepared to pay for quality.
• Ignoring local experience and regulatory knowledge: New Zealand is a large country with a diverse landscape. Local knowledge on everything from soil type to seismic activity can be invaluable in guaranteeing the long-term safety and structural integrity of your project.
• Failing to check testimonials: The value of speaking to the commercial clients of a geotechnical engineer cannot be understated. By checking a firm's testimonials and portfolio of previous projects, you can paint a picture of what the firm is like to work with.

Qualifications and certifications:

• Holds a bachelor's degree in civil engineering, geology or a related field
• Has specialised postgraduate qualifications (e.g. a master's in geotechnical engineering)
• Is a Chartered Professional Engineer (CPEng) certified by Engineering New Zealand

Experience and expertise

• Has experience with projects similar to this one
• Can provide a portfolio of successful, long-term projects
• Has in-depth knowledge of local soil types, seismic risks and environmental factors

Services offered

• Site investigations
• Soil and rock testing
• Slope stability analysis
• Foundation design and assessment
• Earthworks design and monitoring
• Seismic hazard assessments
• Ground improvement solutions
• Retaining wall design
• Infrastructure support
• Erosion and sediment control

Reputation and references

• Has strong endorsements from your professional network
• Has positive reviews on platforms like Google, LinkedIn and Facebook
• Can provide case studies of past projects
• Has testimonials from past clients 
• Is an established firm with a proven track record

Cost considerations

• Provides an itemised quote for easy comparison
• Clearly outlines costs for site investigation, lab testing, design and specialised services
• Offers pricing that aligns with project scope and complexity
• Avoids suspiciously low quotes that may indicate subpar quality

Communication and project management

• Responds promptly to emails and calls
• Demonstrates professionalism and organisation during procurement discussions
• Uses collaborative tools to track project progress
• Sets clear expectations for response times and issue resolution

It's not every day that you need to source geotechnical engineering expertise, so finding the right option for your project can be tricky.

But following the process outlined above, you'll put yourself in a great position to find the best option for your job.

And if you're in need of an experienced geotech team with a long history, a proven track record, and who tick all the right boxes, look no further than Eliot Sinclair.