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If you’re a builder or architect working on residential projects in Canterbury, you already know the engineering piece can make or break a project timeline. The right engineering consultant is one you rarely have to chase – one who understands how building projects actually run.

Here’s what we offer builders and architects who work with us regularly.

A complete residential engineering service under one roof

Branch Consulting covers both geotechnical and structural engineering, which means you’re dealing with one firm instead of two. For most residential projects, that means:

• Geotechnical investigation and report (site-specific, NZS 3604 compliant)
• Foundation design based on the geotechnical findings
• Structural design for the building – beams, bracing, retaining walls, slabs
• Structural calculations and documentation for consent
• Producer Statements for Design (PS1), Review (PS2), and Construction Monitoring (PS4)

Having the geotech and structural work done by the same team means the foundation design is always consistent with the site investigation – no gaps, no finger-pointing between separate firms.

Chartered Professional Engineers

Our structural engineer, Agata Bulska, is a CPEng Chartered Professional Engineer – the highest level of professional recognition for engineers in New Zealand. She is also a Certified Building Consent Processing Officer, which means she understands the consent process in detail from both sides. You get engineering documentation that’s right first time.

We understand programme pressure

We know that delays in engineering sign-off can hold up a consent application, stall a start on site, or push a project into the next weather window. We work to your timeline, not ours. If you have a deadline, tell us and we’ll do our best to meet it.

Standard report turnaround is 5-7 working days from site visit. For urgent projects, contact us to discuss what’s possible.

Straightforward to work with

No account managers, no juniors handing off your file. You deal directly with the engineer doing the work. That means faster answers, clearer communication, and no cost blowout from unnecessary overhead.

Types of projects we handle regularly

• New residential builds – houses and townhouse developments
• Extensions and additions to existing homes
• Sleepouts and minor dwellings
• Retaining walls
• Renovations requiring structural input
• Earthquake damage assessments and repair strategies

Get in touch

If you’re a builder or architect looking for a reliable engineering consultant in Canterbury, we’d like to hear from you. We’re happy to discuss your typical project types and how we can best support your work.

If you own property in Christchurch, you’ve probably seen the letters TC1, TC2, or TC3 somewhere – on your LIM report, your insurance documents, or when talking to a builder. But what do they actually mean, and why do they matter for building on your land?

Background: the Canterbury earthquakes and liquefaction

During the 2010-2011 Canterbury earthquake sequence, large areas of Christchurch experienced liquefaction – a process where saturated, loose soils temporarily behave like a liquid under earthquake shaking. This caused significant and uneven damage to buildings and land across the city.

In response, the New Zealand Government commissioned a detailed assessment of Christchurch residential land. The result was the Technical Category (TC) zoning system, which classifies land based on its risk of liquefaction damage in a future major earthquake.

TC1 – Low risk

TC1 land has low liquefaction vulnerability. Standard NZS 3604 foundation solutions are generally appropriate, and the consent requirements are similar to the rest of New Zealand. Most TC1 sites don’t require a site-specific geotechnical investigation, though this depends on the project type.

TC2 – Moderate risk

TC2 is the most common classification in Christchurch. These sites have moderate liquefaction vulnerability and typically require a site-specific geotechnical investigation and report to support a building consent application. The report will recommend an appropriate foundation system – often a thickened edge or waffle slab – to manage the risk.

A straightforward geotechnical report for a flat TC2 site typically starts from $1,400 + GST.

TC3 – High risk

TC3 land has high liquefaction vulnerability. Building on TC3 land requires more detailed geotechnical investigation and typically a more engineered foundation solution – such as deep piles or ground improvement – to adequately manage the risk. These sites involve higher engineering costs and more complex consent processes.

If your land is TC3, it’s important to get engineering advice early in the design process, before committing to a building design or floor level.

How to find your TC classification

Your TC classification will be listed on your Land Information Memorandum (LIM) report, available from Christchurch City Council. You can also check the Christchurch City Council website for mapping tools.

What does this mean for your project?

Your TC classification directly affects:

• Whether you need a geotechnical investigation
• What foundation type is required
• The cost and complexity of your engineering
• Your building consent process and timeline

At Branch Consulting, we work across all TC classifications. Whether you’re on a straightforward TC2 site or a complex TC3 property, we can carry out the investigation, prepare the report, and design a foundation solution that meets council requirements and is practical to build.

If you’re planning to build a new home, add an extension, or do significant renovation work in Christchurch or Canterbury, there’s a good chance you’ll need a geotechnical report before the council will grant building consent.

Here’s a plain-English guide to when you need one, what it involves, and what it costs.

What is a geotechnical report?

A geotechnical report (sometimes called a site investigation or soil report) is a document prepared by a geotechnical engineer that describes the ground conditions at your property and recommends an appropriate foundation type for your project.

It typically involves a site visit where we carry out soil testing – usually using a Scala penetrometer and hand auger – to understand how the soil behaves at depth. The results are then used to design a foundation that will safely support your building.

When do you need one?

In Canterbury, the following projects almost always require a geotechnical report as part of the building consent application:

• New residential builds
• Major extensions or additions
• Relocatable homes being placed on a new site
• Rebuilds on earthquake-affected land
• Subdivisions requiring new building platforms

Smaller projects – like a minor internal renovation or a deck – usually don’t require one. If you’re unsure, your designer or the Christchurch City Council’s duty planner can advise, or you’re welcome to contact us for a quick steer.

Why Canterbury is different

Ground conditions in Canterbury are genuinely variable. The 2010-2011 earthquakes caused widespread liquefaction across parts of Christchurch, and the Technical Category (TC) zoning system was introduced to classify land based on its susceptibility to future earthquake damage.

Your land will be classified as TC1, TC2, or TC3 – and this classification has a significant effect on what foundation design is required and how much investigation is needed. We cover this in detail in our geotechnical reports guide.

How much does it cost?

A straightforward geotechnical report for a flat TC2 site in Christchurch typically starts from $1,400 + GST. More complex sites – TC3 land, sloping ground, or sites with unusual soil conditions – will require more investigation and carry higher costs.

We always provide a fixed-price quote before starting work, so there are no surprises.

How long does it take?

The site investigation usually takes half a day. We typically deliver the completed report within 5-7 working days of the site visit. If you have a consent deadline, let us know and we’ll do our best to accommodate it.

Who carries out the investigation?

At Branch Consulting, geotechnical investigations are led by James Horan – a Senior Geologist with over 25 years of experience across mining, groundwater, and geotechnical work in Australia, Papua New Guinea, and New Zealand. James is a Member of the Australasian Institute of Mining and Metallurgy (M AusIMM).

Our reports are accepted by Christchurch City Council and meet NZS 3604 requirements.

Ready to get started?

If you’re planning a residential build or renovation in Christchurch or Canterbury and need a geotechnical report, get in touch. We’re happy to have a quick chat about your project before you commit to anything.