When do you need a geotechnical report?

Liquefaction damage in Christchurch following 2015 earthquake

When assessing applications for building consent or subdivision the consenting authority (usually a Council) will need to be satisfied that adequate provision has or will be made to protect the land, building work, or other property that can be affected by the proposed development. Therefore, most, if not all, projects require a geotechnical report whether it be a dwelling extension, a new dwelling, a commercial building, infrastructure etc.

New Zealand’s young and highly variable geology presents unique geotechnical challenges that demand expert analysis. The active seismic setting brings with it the risk of liquefaction, some areas are underlain with soft coastal soils and recent alluvial deposits. Settlement risks are also prevalent due to loose, unconsolidated ground layers, while steep, hilly terrain often results in slope instability hazards such as landslides and rockfalls. With the added impact of climate change driving more extreme weather events, geotechnical risks are intensified — heavy rainfall can saturate and weaken soil structures, further increasing the likelihood of ground movement. Understanding and managing these natural hazards is essential for safe land development, infrastructure resilience, and long-term project success in New Zealand’s complex ground conditions.

These factors underscore the importance of conducting a thorough geotechnical report before commencing any construction project. Such a report provides critical insights into subsurface conditions, enabling better risk assessment, informed planning, and the establishment of appropriate contingencies. Neglecting this step can lead to unforeseen ground conditions that may cause substantial project delays and budget overruns. For instance, a study focusing on New Zealand road projects (Lessing et al. 2017) identified unforeseen ground conditions as a primary factor contributing to cost escalations and project delays . Investing in a geotechnical report is a proactive measure that can safeguard your project against costly surprises and ensure structural integrity.

Get in contact today for your tailored and technical geotechnical report for your project.