Whangaparāoa

Slip remediation and slope stabilisation for 48 Riverhaven, Whangaparāoa - drainage, retaining, and civil works under constrained steep terrain, subcontracting for Fulton Hogan with zero incidents.

We were engaged by Fulton Hogan to provide specialist civil, drainage, and slope stabilisation works after a significant slip on a narrow street in Whangaparāoa. Being subcontracted by New Zealand’s largest civil and roading contractor was a major vote of confidence in our capability and trustworthiness.

Scope & Challenges

• A substantial land slip occurred, threatening the road’s stability, adjacent properties, and existing services.
• The site was extremely constrained: steep slopes, limited working width, minimal allowance for staging or spoil storage, and adjacent vegetation/native bush to protect.
• The street was narrow, so every movement, delivery, machine placement, and crane lift needed exact sequencing, traffic and pedestrian management.
• Ground conditions were variable, likely with wet soil, soft zones, and slope instability risks.
• Safety, environmental protection (erosion control, sediment runoff, interface with native bush), and coordination with Fulton Hogan’s main works and design teams were critical.

Key Deliverables & Solutions

• Capping beam: we worked around a robust capping beam (reinforced concrete) at the toe or critical location of the slip zone to stabilise the slope and tie structures together.
• Drainage & relief works: to prevent further slippage, we installed new drainage, collector pipes, subsoil drainage, and relief drains to lower groundwater pressures.