DATE OF PROJECT 2025
LOCATION AUCKLAND
Overview
This project involves waterproofing and concrete repair works for a high-rise apartment building in Auckland’s CBD. The 34-storey building required remediation work on four levels featuring extensive balconies. Sansom secured the contract to install specialised waterproofing systems, including Hydrotech membrane on the balconies and Casali warm roof systems for the roof areas.
A significant highlight of this project is the introduction of Hydrotech’s premium system warranty – a first for Auckland. This warranty covers both materials and installation quality, with each layer of work being inspected, photographed, and approved by a third-party engineer and Hydrotech’s technical team throughout the installation process.
Our Involvement
Sansom was selected for this project based on their experience with complex waterproofing systems and their comprehensive service offering. Providing both waterproofing installation and concrete repair services allowed for better coordination between connected trades compared to using multiple subcontractors.
The scope included installing multiple waterproofing systems:
The Hydrotech system installation involves a labour-intensive process requiring precise application of multiple layers: derma primer, hot liquid membrane (Hydrotech 6125), Flex Flash F reinforcement, another layer of hot liquid membrane, and finally the Olympia protection sheet. Before installation, the team conducts moisture testing on the concrete substrate to ensure levels comply with manufacturer specifications, followed by pull tests to verify proper adhesion.
Challenges and Solutions
Several key challenges were addressed throughout the project:
Complex Logistics: With no crane access available, vertical movement of materials presented significant difficulties, particularly for the Hydrotech kettle – a crucial piece of equipment used to melt Hydrotech blocks into hot rubber liquid. This kettle needs to be positioned close to work areas for safety reasons when handling hot liquid buckets. Sansom proactively collaborated with the main contractor to develop effective solutions for material movement.
Design vs. On-Site Reality: Once demolition revealed the actual substrate conditions, the team encountered variances from the consented architectural plans. Drawing on their experience from similar projects, Sansom’s team took a proactive approach, promptly sending RFIs to the main contractor with expert recommendations. This approach helped speed up the design process and avoided delays from extended discussions about design versus buildability.
Coordination and Protection: The project required carefully sequenced work involving multiple visits to each area. Setting clear expectations with the main contractor regarding work programming and the temporary protection of completed membranes was essential to prevent damage from subsequent trades. Additionally, moisture protection during installation was critical, with the client providing shrink wrap protection to prevent water ingress during warm roof system installation.
Outcome
The Sansom team, led by Contracts Manager Andrew Baird, had recently installed 6,000m² of Hydrotech on a similar project and brought valuable expertise to the intricate detailing required. Their knowledge and proactive approach in identifying potential issues have been instrumental in maintaining high-quality workmanship.
Despite the complexities involved, the collaboration between Sansom’s team and the main contractor has created a productive working environment focused on producing the best outcome for the work.
The project demonstrates the value of Sansom’s integrated approach to waterproofing and concrete remediation, allowing for streamlined communication, maintained quality standards, and ultimately delivering results for this significant remediation project.
