Retaining walls. Stable slopes.
Retaining wall and slope stabilisation design across Christchurch and Canterbury and throughout New Zealand, from timber pole and reinforced concrete walls to tied-back systems, soil nails, rock anchors and engineered slope stabilisation.
Designed for the ground behind it.
Every retaining wall responds to the ground it holds, the water within it and the loads above it. We bring structural and geotechnical engineering together to design the wall, foundations, drainage and any required anchors as one system, from simple timber pole walls to complex tied-back and slope stabilisation solutions.
Geotechnical EngineeringWalls we design.
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
Cost-effective retaining for residential and commercial sites, from low garden and driveway walls to specifically engineered cantilevered and tied-back timber pole systems for greater retained heights and challenging ground conditions.
Masonry walls
Reinforced masonry retaining walls for standalone retaining, basements, garages and walls integrated with the building foundation, designed for earth pressure, surcharge, groundwater and structural loads as part of the overall building and foundation system.
Reinforced Concrete walls
Reinforced concrete retaining walls for basements, foundations, boundary retaining and heavily loaded sites, including cantilever, counterfort and anchored systems designed for higher retained heights, surcharge loads and demanding ground conditions.
Tied-back and anchored walls
Where cantilevered retaining alone is not practical, tiebacks, ground anchors or rock anchors can transfer loads into stable ground behind the wall, providing efficient solutions for higher walls, restricted sites and challenging slopes.
Soil nails, shotcrete and anchored stabilised mesh
ngineered slope stabilisation using soil nails, rock anchors, reinforced shotcrete or anchored high-strength mesh systems — designed to control shallow instability, rockfall and localised slope failures on steep cuts and challenging terrain.
Gabion wall
Rock-filled gabion retaining systems providing a flexible, free-draining solution for retaining, slope support and erosion control, particularly suited to sites where drainage and tolerance of ground movement are important.
Crib wall
Interlocking timber or precast concrete crib retaining systems filled with free-draining granular material, providing a robust gravity retaining solution for residential, commercial and hillside sites where space allows for a wider wall footprint.
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.
How it runs.
From understanding the ground and what needs to be retained to a practical, buildable and certified retaining solution.
- 01
Assess the site
We assess the ground, existing levels, proposed excavation or fill, nearby structures, groundwater and any signs of instability before design begins. Understanding what needs to be retained, and the constraints around it, determines the most appropriate retaining solution.
- 02
Test the ground
Site-specific ground investigation establishes the soil profile, bearing conditions, groundwater and the parameters needed for retaining wall design. Investigation can range from hand auger and Scala testing to CPTs, machine boreholes and rock assessment for larger or more complex retaining systems.
- 03
Model where needed
For higher walls, deep excavations and complex ground conditions, geotechnical modelling is used to assess slope and global stability, potential failure mechanisms and the interaction between the retaining system and surrounding ground.
- 04
Design and detail
The retaining system is designed for the ground conditions, retained height, surcharge, groundwater and structural loads, then fully detailed for construction, including the wall, foundations, reinforcement or anchors, drainage, backfill and connection details.
- 05
Certification & Sign off
Engineering documentation and certification from design through to completion, including PS1, Building Consent or exemption support, construction monitoring and PS4 sign-off where required
What the wall is resisting
Behind every retaining wall is a combination of soil pressure, groundwater and surcharge loads. The wall, foundation, drainage and, where required, anchors work together to resist these forces and maintain stability. The section below illustrates the key elements considered in retaining wall design.
What we assess.
The ground, water, loads and stability conditions that determine whether a retaining system will perform as intended.
Site stability
Whether the slope is stable before anything is built on it.
Geohazards
Potential geohazards including slope instability, landslides, mass movement, erosion, rockfall and ground deformation are identified early so they can be incorporated into the retaining or stabilisation design.
Groundwater
Groundwater levels, seepage and potential water pressures behind the wall are assessed as part of the design. Appropriate subsoil drainage, free-draining backfill and controlled discharge are incorporated to prevent water pressure from compromising the retaining system.
Surcharge
Additional loads from buildings, driveways, vehicles, stored materials or sloping ground behind the wall are assessed and incorporated into the retaining wall design.
Foundation options
The founding conditions, bearing capacity and embedment required to support the retaining system, from shallow footings and embedded poles to piles, ground beams and anchored foundations, designed to suit the ground and wall loads.
What a geotechnical report contains
What retaining work looks like.
From timber pole and concrete retaining walls to anchored excavations, soil nails, stabilised mesh and complex slope stabilisation — examples of retaining and ground support solutions from construction through to completion.
A wall that moves takes the slope with it.
A retaining wall is part of the ground-support system, not simply a structure in front of it. Inadequate foundations, drainage or wall capacity can lead to movement, cracking and deformation of the retained ground, potentially affecting buildings, driveways and services above. Proper investigation and coordinated structural and geotechnical design address the ground, water and wall as one system.
Get the retaining solution right.
Send us the site address, the height to be retained, what sits above and below the wall, and any available plans or photographs. We can review the site constraints and advise on the appropriate investigation, retaining system and next steps.