Looking at building a new home or altering your existing home?
Council often requires a geotechnical assessment be undertaken to check the ground conditions and assess geotechnical risks such as land instability or weak ground. The level of geotechnical input will vary depending on what is to be constructed, the topography of the site and the underlying soil type. KGA will look at each site on a case by case basis, utilising our knowledge of the area, to a tailor a geotechnical report specifically for your needs and to identify any issues early, so they don’t become major problems come building time.
What do I need to do to get a geotechnical report done?
Give us a call and you will speak to one of our engineers who will talk through your project with you to understand what you are looking at doing. From there, we will look at the information provided and information for the area to determine what level of geotechnical input is required to address your needs. We can be contacted on Auckland: (09) 478 6655 and Christchurch (03) 3435302.
What is involved in a geotechnical report?
This varies depending on the project. In most cases, the work will first involve a walk over inspection of the site to assess surface features. We will then undertake hand auger drilling to check the soil type and its strength, followed by a return visit to measure groundwater levels. This information will be used to prepare a report, suitable for Building and/or Resource Consent application and will provide details for your project such as foundation options, retaining wall design parameters and considerations to be taken into account during construction to minimise potential issues cause by the ground conditions.
How much does it cost?
The costs vary based on the location of the site, the number of boreholes required, and the complexity of the project. Standard geotechnical reports are generally between $2500 to $4000.
How long does it take?
We aim to have a quote back to you within a couple of days. The geotechnical report will generally take approximately 20 to 25 working days to complete.
What information do I need to provide?
Any information you have on the project will be useful, including topographical surveys, architectural drawings, historical geotechnical reports. However, even if all you know is that you want a new house ‘somewhere over there’, we will still be able to prepare a geotechnical report. The only difference is that the report will be slightly broader to provide options for your project, rather than giving specific details.
What does the drilling involve?
The most common type of drilling is hand auger drilling. It is undertaken by one of our technicians and as it is done by hand, there is no noisy or large equipment to bring onto site. A hand auger borehole is approximately 50mm diameter and we hand auger to a maximum depth of 5m, if possible. This is then followed up with a Scala penetrometer probe (rods which are pushed into the ground by a dropped hammer) to give us information beyond the depth of the borehole and is useful to determine where soils transition to rock. We can complete 4 hand auger boreholes a day.