Contact Us
Commercial Building image
2011

Waitangi Museum

Location: Waitangi, Bay of Islands, Far North District

Client: Waitangi National Trust
Salvation Army Auditorium Building
2020

Salvation Army Auditorium Building

Location: Aubrey Street, Whangarei

Client: The Salvation Army
Services

Slope Engineering 

Ensuring Slope Stability

Northland’s hills, soft clay soils and high rainfall make slope movement a real risk — and a costly one when it threatens a home or cuts off access. RS Eng investigates the causes of existing land movement and the triggers of potential future movement, then designs practical measures to manage the risk: retaining structures, ground and surface drainage, slope reprofiling and erosion control. Where a slip has affected an insured property, we can work with your insurer or the Natural Hazards Commission Toka Tū Ake (formerly EQC) to design cost-effective mitigation.

Slope Engineering Services: 

Our experience and tools help us understand why ground is moving — or might move — and design effective measures to protect properties and infrastructure.

Let's work together

Slope stability analysis

Landslide risk assessments

Retaining wall and slope reinforcement design

Erosion control measures

Geotechnical monitoring

When Do You Need Slope Engineering?

Slope engineering is required or strongly recommended in the following situations:

Request an Assessment

  • Building on a slope
    Hillside and elevated sites need slope stability assessment and often retaining and drainage design. Council will usually require this as part of a building or resource consent on sloping ground.
  • After a slip or land movement
    If your property has experienced a slip, an assessment identifies the cause and extent before any repair — so the remediation fixes the underlying problem, not just the surface.
  • Buying hillside or lifestyle land
    A slope stability assessment before purchase tells you whether the land is stable enough for your plans and what it may cost to build safely — valuable across Northland’s hill-country sections.
  • Making an insurance or Natural Hazards Commission claim
    Where a landslip has affected an insured property, we can work with your insurer or the Natural Hazards Commission Toka Tū Ake (formerly EQC) to assess the damage and design appropriate mitigation.

What Makes Northland Slope Conditions Different?

Northland’s geology and climate make slope movement more common here than in many parts of the country. Knowing the local triggers is why our mitigation works.

Request an Assessment

  • Soft, clay-rich soils and the Northland Allochthon create inherently unstable ground in many areas. These materials lose strength when wet and are prone to creep and slip.
  • High and intense rainfall is the most common trigger. Prolonged wet periods and ex-tropical storms saturate slopes and drive failures — as recent severe weather events across the region have shown.
  • Steep and modified slopes — including sites cut or filled for building — change how loads and water move through the ground, sometimes destabilising slopes that were previously stable.
  • Poor drainage concentrates water in the worst places. Managing ground and surface water is often the single most effective — and cost-effective — way to stabilise a Northland slope. An RS Eng slope assessment targets the actual cause of movement on your site, so mitigation addresses the real problem rather than the symptom.
How the Process Works

We follow a clear process to investigate the slope, identify the cause, and design mitigation suited to the site and the risk.

Request an Assessment

  • Step 1 — Get in touch
    Tell us about your site and any signs of movement. We’ll advise on the investigation required and provide a fee estimate.
  • Step 2 — Site investigation
    Our engineers assess the slope and ground conditions — and, where needed, carry out testing — to understand stability and the drivers of movement.
  • Step 3 — Analysis and design
    We analyse the slope’s stability and design mitigation: retaining structures, drainage, reprofiling or stabilisation measures, sized to the conditions and the risk.
  • Step 4 — Reporting and documentation
    You receive a report and design suitable for consent and construction (and for insurer or Natural Hazards Commission processes where relevant). We’ll confirm turnaround when we scope the work.

FAQs

A combination of factors — steep ground, soft or clay-rich soils, heavy or prolonged rainfall, poor drainage, undercutting at the toe of a slope, and earthworks that change the loading. We investigate to identify which are at play on your site.

Make the area safe, then get a slope assessment to understand the cause and extent before any repair. We can investigate, advise on immediate risk, and design a remediation that addresses the underlying cause.

Yes. Where a natural hazard such as a landslip has affected an insured property, we can work with your insurer or the Natural Hazards Commission Toka Tū Ake (formerly EQC) to assess the damage and design cost-effective mitigation.

Yes. We design retaining structures, subsoil and surface drainage, slope reprofiling and other stabilisation measures, sized to the geotechnical conditions and the risk.

Yes. A slope stability assessment before purchase or design tells you whether the land is stable enough for your plans and what it may cost to build safely.