Welcome to our Sunshine Coast geotechnical office. We provide comprehensive subsurface investigation, foundation design, and construction monitoring services tailored to the region's unique coastal and hinterland environments. Our team combines consolidated regional experience with calibrated field equipment to deliver code-compliant reports for residential, commercial, and infrastructure projects. Whether you are planning a new development near Maroochydore or a slope in the hinterland, we support every phase from site characterisation to construction verification. For more on our approach, see our slope stability analysis and soil mechanics study pages.
Technical reference image — Sunshine Coast
Scope of work
The Sunshine Coast region is underlain by complex geology, including Mesozoic sedimentary rocks of the Maryborough Basin, Tertiary basalts from the Glass House Mountains volcanic province, and extensive Quaternary alluvial and coastal deposits. In low-lying areas such as Maroochydore and Caloundra, soft estuarine clays and silts (often associated with the Bli Bli Formation) can exceed 20 metres in thickness, presenting challenges for foundation design due to high compressibility and low bearing capacity. The coastal sand masses, such as the Coolum and Peregian beach ridges, consist of well-graded silica sands with variable groundwater levels influenced by tidal fluctuations and seasonal rainfall. In the hinterland, residual soils derived from weathered phyllite and greywacke of the Nambour Basin form colluvial slopes prone to shallow translational slides during intense rainfall events. Groundwater is generally shallow near the coast (1–3 metres below surface) and deeper in elevated areas. Seismic hazard is low to moderate, but liquefaction potential exists in loose, saturated sands. Our investigations address these conditions using advanced techniques like electrical resistivity VES to map subsurface variability.
Area-specific notes
Our firm brings deep local knowledge to every Sunshine Coast project. We have completed numerous investigations across the region—from coastal subdivisions in Kawana to rural residential lots in Maleny—giving us firsthand understanding of the local soil profiles, groundwater behaviour, and council requirements. Our in-house laboratory is calibrated for high-volume consolidation and triaxial testing, and we routinely coordinate with Sunshine Coast Council, private certifiers, and local earthworks contractors. By combining field experience with rigorous compliance to Australian standards, we provide reliable, defensible geotechnical advice for projects of all scales.
All geotechnical work in Australia follows standards set by Standards Australia, including AS 1726 (geotechnical site investigations), AS 2870 (residential slabs and footings), and AS 4678 (earth-retaining structures). For foundation design, we reference AS 2159 (piling) and AS 5100 (bridge design) where applicable. In situ testing follows AS 1289.6.3.1 (SPT) and AS 1289 methods for soil classification and compaction. Seismic assessments are guided by AS 1170.4, and slope stability analyses adhere to AS 4678 and the Australian Geomechanics Society’s practice notes. All laboratory testing is conducted in our NATA-accredited facility to ensure compliance with project specifications.
Frequently asked questions
What are the typical soil conditions I should expect for a new home site near the Sunshine Coast beachfront?
Beachfront properties often sit on loose to medium-dense sands underlain by estuarine clays or silts at depth. Groundwater is typically shallow, within 1–2 metres of the surface, and can fluctuate with tides. Bearing capacity may be adequate for shallow footings in clean sands, but compressible clays deeper down can cause long-term settlement. A site-specific investigation with test pits or boreholes is recommended to assess soil layering and groundwater conditions before design.
Does the Sunshine Coast Council have specific geotechnical reporting requirements for development applications?
Yes. Sunshine Coast Council generally requires a geotechnical report for any development on steep slopes (greater than 15%), in areas identified as having acid sulfate soils, or where fill is proposed. The report must be prepared by a registered professional engineer and address site stability, foundation design, and erosion control. We are familiar with these local requirements and ensure our reports meet the council’s guidelines, including referencing relevant Australian standards.
What Australian standards apply to geotechnical investigations in Queensland?
The key standards are AS 1726-2017 for geotechnical site investigations, AS 2870-2011 for residential slabs and footings, and AS 2159-2009 for piling. For retaining walls and slopes, AS 4678-2002 applies. Seismic design follows AS 1170.4-2007. All field and laboratory testing must comply with the AS 1289 series. Our reports clearly state which standards were used so that certifiers and engineers can easily verify compliance.
What is the most common foundation issue encountered in Sunshine Coast residential projects?
The most common issue is differential settlement caused by variable subsurface conditions—especially where reactive clay layers (like the Bli Bli Formation) are present beneath more competent sands. In the hinterland, slope instability due to colluvial soils and high seasonal rainfall is also frequent. Proper site investigation, including boreholes and soil reactivity testing, helps identify these risks early and allows for appropriate foundation design, such as stiffened rafts or deep piers.
