Retaining Wall Design & Slope Stabilisation
Specialist geotechnical and structural engineering solutions for retaining walls and slope stabilisation across Christchurch, Canterbury and New Zealand. From timber pole and reinforced concrete walls to tied-back retaining systems, soil nails, rock anchors and engineered slope protection.
Engineered Retaining Walls. Stable Slopes.
We provide practical, cost-effective retaining wall design and slope stabilisation solutions, combining structural and geotechnical engineering expertise. From timber pole and reinforced concrete walls to complex anchored retaining systems, soil nails and rockfall protection.
Geotechnical EngineeringRetaining Wall Design Solutions
From simple cantilevered timber pole walls to masonry, reinforced concrete, crib, segmental block, tied-back and anchored retaining systems, selected and designed to suit the retained height, ground conditions, groundwater, surcharge loads and site constraints.
Timber Pole Retaining Walls
Practical and cost-effective retaining solutions for residential and commercial projects, from low garden and driveway walls to specifically engineered cantilevered and tied-back timber pole systems for greater retained heights and challenging ground conditions.
Reinforced Masonry Retaining Walls
Engineered reinforced masonry retaining walls for residential and commercial projects, including standalone retaining structures, basements, garages and walls integrated with building foundations. Designed to resist earth pressures, surcharge loads and groundwater effects while providing durable, practical structural solutions.
Reinforced Concrete walls
Robust, specifically engineered retaining solutions for basements, building foundations, boundary walls and heavily loaded sites. Our designs include cantilever, counterfort and anchored reinforced concrete walls, tailored to accommodate greater retained heights, surcharge loads and challenging ground conditions.
Tied-back and anchored walls
Specialist retaining solutions for steep slopes, restricted sites and greater retained heights where conventional cantilever walls are impractical. Our designs incorporate ground anchors, rock anchors and tied-back systems to provide structural stability and safely transfer loads into competent ground or rock.
Soil nails, shotcrete and anchored slope stabilised mesh
Specialist slope stabilisation solutions using soil nails, rock anchors, reinforced shotcrete and anchored high-strength mesh systems. Our designs address shallow slope instability, rockfall hazards and localised ground failures on steep slopes, exposed cut faces and challenging terrain.
Gabion Retaining Walls
Versatile and cost-effective rock-filled retaining systems for slope support, erosion control and landscaping applications. Gabion walls provide flexible, free-draining solutions, particularly suited to sites with challenging ground conditions, groundwater issues and potential ground movement.
Crib Retaining Walls
Durable and cost-effective gravity retaining solutions using interlocking timber or precast concrete crib systems filled with free-draining granular material. Ideal for residential, commercial and hillside developments where effective drainage, structural stability and a wider wall footprint can be accommodated.
Mechanically Stabilised Earth (MSE) walls
Engineered reinforced-soil retaining systems using layers of geogrid or other reinforcement within compacted structural fill to create a stable soil mass. MSE walls can incorporate segmental block, concrete panel or other facing systems and are well suited to higher retaining walls, embankments, commercial developments and sites where a flexible, efficient retaining solution is required.
Our Retaining Wall Design Process
From understanding the ground and what needs to be retained to a practical, buildable and certified retaining solution.
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Assess the site
From initial site assessment and geotechnical investigations through to structural design, building consent and construction monitoring, we deliver practical, cost-effective and fully engineered retaining wall solutions tailored to your project.
- 02
From Ground Investigation to Construction
Understanding ground conditions is essential for safe and cost-effective retaining wall design. We undertake site-specific geotechnical investigations, including hand augers, Scala testing, CPTs and machine boreholes, to assess soil strength, groundwater conditions and ground stability, providing reliable parameters for retaining wall design.
- 03
Geotechnical Modelling and Stability Assessment
For higher retaining walls, deep excavations and challenging ground conditions, we undertake geotechnical modelling and stability analyses to assess potential failure mechanisms, global slope stability and soil–structure interaction, ensuring safe, efficient and reliable retaining wall designs.
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Structural Design and Detailing
We develop site-specific retaining wall designs considering ground conditions, retained heights, surcharge loads, groundwater and structural requirements. Our detailed engineering drawings and specifications cover foundations, reinforcement, anchors, drainage, backfill and structural connections to ensure safe, practical and buildable solutions.
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Engineering Certification and Sign-Off
We provide engineering support from design through to construction completion, including PS1 design certification, building consent and exemption assistance, construction monitoring and PS4 construction review certification where required, ensuring retaining wall works comply with approved designs and relevant building standards.
Understanding Retaining Wall Forces
Retaining walls must resist lateral earth pressures, groundwater forces and surcharge loads from nearby structures or sloping ground. Our designs consider these forces alongside foundation bearing capacity, sliding, overturning and overall stability. The illustration below highlights the key engineering principles behind a safe and reliable retaining wall system.
Key Retaining Wall Design Considerations
Every retaining wall requires careful assessment of ground conditions, soil strength, groundwater, surcharge loads and overall stability. Our engineering assessments address these critical factors to deliver safe, durable and cost-effective retaining solutions tailored to each site.
Site stability
Assessment of existing ground and slope stability, including potential landslide risks, global failure mechanisms and the effects of proposed retaining works on surrounding land and structures.
Geotechnical Hazards Assessment
Identification and assessment of potential geotechnical hazards, including landslides, slope instability, erosion, rockfall and ground deformation, to ensure these risks are appropriately addressed in the retaining wall or slope stabilisation design.
Groundwater and Drainage Assessment
Assessment of groundwater levels, seepage conditions and potential hydrostatic pressures behind retaining walls. Our designs incorporate appropriate subsoil drainage, free-draining backfill and controlled water discharge to minimise water pressure buildup and maintain long-term structural stability.
Surcharge and External Loads
Assessment of additional loads imposed by nearby buildings, foundations, driveways, vehicles, stored materials and sloping ground. These surcharge loads are incorporated into the retaining wall design to ensure adequate structural capacity and long-term stability.
Foundation Design and Bearing Capacity
Assessment of soil bearing capacity, founding depths and ground conditions to determine suitable retaining wall foundations. Our designs include shallow and embedded footings, piled foundations, ground beams and anchored systems, tailored to the structural loads and site-specific geotechnical conditions.
What a geotechnical report contains
Our Retaining Wall and Slope Stabilisation Projects
Explore examples of our retaining wall and slope stabilisation projects, including timber pole and reinforced concrete walls, anchored retaining systems, soil nailing, shotcrete and stabilised mesh. From construction through to completion, these projects demonstrate our practical engineering solutions for challenging ground conditions.
A Retaining Wall Is Only as Strong as the Ground Supporting It
Retaining walls do more than hold back soil — they protect the stability of surrounding land, buildings and infrastructure. Inadequate foundations, drainage or structural design can lead to wall movement, ground deformation and costly damage. Our integrated structural and geotechnical engineering approach ensures the ground, water and retaining system are considered together to deliver safe, durable and reliable solutions.
Let's Find the Right Retaining Solution for Your Site
Planning a retaining wall or dealing with challenging ground conditions? Contact our structural and geotechnical engineering team for expert advice. Share your site details, proposed retaining height and any available plans or photographs, and we'll help identify the most suitable retaining solution and next steps.