Geotechnical

Geotechnical investigations and reports

When planning your next development, it’s important to make sure that ground conditions are suitable to build on. Slope stability issues, fill and clay concerns, or piling requirements all need to be considered (and sometimes mitigated) before construction can start. That’s where a geotechnical engineer comes in.

With the right tools and experience, an engineer can identify potential problems before you design your foundation and structure. They’ll assess the ground at your planned build site and write a geotechnical report that identifies any potential issues and recommends a course of action.

STA Consulting Engineers are one of Australia’s leading specialists in geotechnical engineering for residential and multi-storey structures. Our geotechnical services include geotechnical investigations, slope stability analysis, and geotechnical reports. And with our own NATA accredited laboratory for thorough testing and analysis, you’ll get accurate reports and recommendations sooner so you can get on with the build.

Our geotechnical engineering process

From initial specs through to final reports, here's how we provide clients with geotechnical engineering services

Review

Your geotechnical engineer will always start by reviewing your specifications and the site conditions.

Walk over

Next, they'll complete a walk over the site to perform risk assessments. Your engineer may drill holes, take soil samples, dig trenches, bore, and even do a seismic survey.

Site assessment and database check

Back at the office, they'll process the soil samples in our NATA accredited lab, assess the site, and reference the database for further information (where needed).

Report and QA review

After the risk assessment report is complete, it's checked by another engineer for quality assurance to make sure nothing's missing.

Reports and certification issued

Finally, your reports and certification are issued. They should be in your inbox within 10 days after your initial site assessment (depending on your local government area).

Why choose us?

Why choose STA for geotechnical engineering?

Experts in local geology

With almost 30 years’ soil testing experience and hundreds of geotechnical investigations every year, we have a deep understanding of local conditions throughout Queensland and New South Wales.

Site-specific foundation design

STA Consulting Engineers offers full-service engineering. We can design your foundations and structure to suit the ground conditions and the surrounding areas.

Analysis in our own NATA lab

We have our own NATA accredited laboratory where we thoroughly test and analyse materials. Because we're in full control over the testing process, our team can promise extremely reliable data for every project.

Regional soil profile maps

With decades of data across hundreds of thousands of soil tests, we've developed local and regional profiles of soil compositions, along with wind ratings, bushfire assessments, and other “site estate specific” data.
"I have been associated with STA Consulting for over 20 years back in the day with Cooper Constructions, Cooper Connell & now Invision Homes for the past 13 years, we have always found their service and attention to detail the best in the business, their engineers have always been very helpful in explaining issues when they arise. We would have no hesitation in recommending their services to anybody in the industry."

Roger Connell // Managing Director

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Get started with a geotechnical engineer

Request a quote and we’ll get back to you within 24 hours or call (07) 3071 7444 (QLD) or (02) 4032 6450 (NSW) to chat with our team right away

Our work

Recent geotechnical projects

Here are some recent builds where we've provided geotechnical engineering services

FAQs

Tell me more about geotechnical engineering

What is geotechnical engineering?

Geotechnical engineering involves using science, tools, and techniques to understand the ground beneath a structure. Some geotechnical engineers (like STA) focus on how soil, rock, and groundwater could impact a building’s performance and design to minimise risk and maximise safety and longevity.

Geotechnical engineering informs the designs and materials for your building’s foundations, footings, and structure. It uncovers the level of earthworks and excavation needed, including temporary/permanent stability due to the excavation. It’s one of the first – and most critical – steps in a building project.

Why and when is it needed?

Geotechnical engineering minimises the risk that something could go wrong with your building because of the ground underneath it. When you know how the ground will affect your structure, you can make the right decisions from the start about where to build and what designs and materials to use.

Without a geotechnical investigation and report, you’re taking a significant risk that you’ll discover unexpected problems during (or even after) the build. This could massively bump up project costs if you need to adjust the design, change the location, redo the footings, purchase different materials, or repair damage.

Most of the time, it’ll make sense to get a geotechnical engineer in as early as possible – once you’ve secured the land and you know where you’d like to develop. Their reports will impact the build location, materials, and project costs, so the sooner you get them onsite, the better.

What's the soil bearing capacity standard in Australia?

Soil bearing capacity refers to the total building load a ground can handle without the soil over-settling or compressing.

The Building Code of Australia (BCA) requires a minimum bearing pressure of 100kPa for under strip and pad footing systems and 50kPa for under slab footings, as long as it’s a 1-2 storey building of typical construction methods outlined in the standards.

Some soils that are wet, sandy, or poorly compacted tend to have very low soil bearing pressure which makes them unsuitable for development. Your geotechnical engineer will test the ground to confirm suitability and include this information in your geotechnical or soil report report.

What's a geotechnical investigation?

A geotechnical engineer does “geotechnical investigations” where they visit the site marked for development, observe the soil, rock, and bedrock, and take samples for testing and analysis. On top of this, they’ll consider natural hazards like debris flows, rockfalls, landslides, sinkholes, and earthquakes. This is to understand what’s going on in the ground and how it may impact a building.

What's a geotechnical report?

After the geotechnical investigation is complete, your engineer will usually put their findings into a geotechnical report. This includes information on the site conditions, along with recommendations for the construction or design. The report is used during design and construction to guide decisions affecting the building’s foundation and structure, and it may be referred to post-completion to resolve claims.

Most geotechnical reports include:

  • Subsurface soil profile
  • Lab test results
  • Groundwater info
  • Subsurface soil profile
  • Analysis of subsurface data
  • Design recommendations
  • Solutions for anticipated issues

What's the average turnaround time for geotechnical reports?

Our average turnaround time is 10 days for metropolitan areas. In regional areas turnaround time averages 18 days, as we need to allow for travel time.

Want to know more about geotechnical engineering?

Other services

Soil testing

Foundation design

Structural design

Building hydraulics

Building inspections

Get started with a geotechnical engineer

Request a quote and we’ll get back to you within 24 hours or call (07) 3071 7444 (QLD) or (02) 4032 6450 (NSW) to chat with our team right away