Reports written to be consented.
Geotechnical reports for building consent across Christchurch and Canterbury. The ground investigated, classified, and written up to stand at council.
The document your consent stands on.
Councils require a geotechnical report for most building and resource consents. It is the evidence that the ground under the build has been investigated, not assumed. You get the site tested, every layer classified, and the founding recommendations the structural design will use, written for the council officer who reads it. A vague report costs money twice, once at council and again when whoever designs the foundation has to assume what the report would not say.
Geotechnical EngineeringWhen you need one.
A geotechnical report is commonly required for consent on:
A new dwelling
The most common trigger, on any site the council has flagged.
Additions and alterations
Where new load lands on existing ground, or the footprint changes.
Subdivision
Small and large scale, to confirm the land will carry what is planned for it.
Multi-storey and commercial
Larger loads and larger consequences want deeper investigation.
Infrastructure works
Where the ground itself is the structure.
TC3 and liquefaction-prone sites
Canterbury ground the council requires to be investigated in detail.
TC1 to TC3 explained
How it runs.
From confirmation to the report on your desk.
- 01
Site visit and investigation
Testing commences within two to three weeks of confirmation, on the site itself.
- 02
Shallow and deep testing
Both run on the same visit, with the shallow holes described before anything deeper is pushed.
- 03
Classify and log
Each layer described, measured and recorded against its depth, so another engineer can check the log against the ground it came from.
- 04
Write the report
Findings and founding recommendations, issued two to three weeks after testing.
- 05
Producer statement
Where the design supports it, signed and issued.
What a bore log records.
Every site is different. An investigation logs the ground top-down, the way a bore log reads, from the topsoil to the layer that will carry the load. The depths below are indicative, not a specific site.
How we test the ground.
The right method for the site and the load it will carry.
Hand augers
Shallow sampling to 3.0m, logging the layers by hand.
Shear vane
The undrained strength of cohesive soils, measured in place.
Scala Penetrometer
A fast index of shallow ground strength to 3.0m.
Cone Penetrometer Test
CPT to a minimum of 15m below ground level, a continuous strength profile.
Machine borehole
Where CPT cannot be undertaken, drilled and sampled deeper.
What the investigation looks like.
Ground investigation work, frame by frame, from the rig on site to the section drawn out of the log.
Skip the report, pay at consent.
Consent on ground you have not seen is a gamble. The council can ask for a report anyway, and the build stops while you get one. Worse is the report done too late, after the footings are in and the ground turns out softer than assumed. The report is the cheapest part of the job. It is also the part that decides whether the rest holds.
What a geotechnical report containsGet the ground on record.
Send the plans and the site address. We will confirm whether the council will want a report on this ground, and what producing one would take.