InterGroup was engaged by McIntosh Commercial Construction Ltd to deliver hydro demolition services at Merivale Mall in Christchurch. The project required careful removal of concrete to address structural damage caused by the Christchurch earthquakes and prepare the site for new reinforced slabs. Work was carried out under tight site constraints with strict noise and safety requirements – requiring careful planning and execution to maintain efficiency and quality.
Stage one of the project involved cutting the concrete slab to prepare the area for the next phase of works.
What We Did
Stage 1 focused on laying the foundation using our Aqua Cutter 710V to remove concrete precisely while protecting existing reinforcing steel. Stage 2 introduced a freshwater tank to manage excess solids as water filtration challenges arose. Stage 3 covered roughly the same volume as the first two stages combined and was completed in just seven days – faster than the estimated 10 days – including full clean-up. In total, our team cut over 600mm of concrete using a 2.7mm nozzle at 1500psi. To minimise environmental impact we filtered and recycled water on-site and continuously monitored vibrations, gas levels and ventilation to ensure safe, efficient operations.
Clarifier system filtering and reusing water on-site.
Client Feedback
“McIntosh Commercial Construction commissioned InterGroup to provide hydrodemolition services on our underground project in Merivale. They came highly recommended by other trade professionals, particularly for their strong health and safety practices and their exceptional knowledge and skill in hydro demolition.
Throughout the project, InterGroup’s involvement proved invaluable. Their expertise extended well beyond the demolition scope, particularly in managing the complex environmental requirements associated with the works. Their innovative filtration strategy ensured compliance with environmental standards and played a crucial role in the project’s overall success.
Had it not been for InterGroup’s proactive approach, technical capability, and commitment to best practice, the project would not have achieved the same level of efficiency or environmental performance.”
Managing Director at McIntosh Commercial Construction Ltd,
Innovative technology to enhance project outcomes
Our use of the Aqua Cutter 710V was essential to the project’s success – delivering precise, controlled demolition without vibration. Its use significantly increased productivity, reduced operator fatigue and improved working conditions. The non-vibrational operation allowed us to maintain structural integrity while achieving uniform and accurate cuts.
Overall, the technology enabled safer, faster and more efficient demolition while reducing disruption to surrounding businesses.
Meeting complex challenges
The project presented several challenges, including noise management due to nearby businesses, water filtration limits and a compact site footprint. Noise pads kept levels below 85 decibels, while our freshwater tank and clarifier system ensured suspended solids were effectively managed.
Working in limited space required careful planning around equipment movements and safety. Non-vibrational demolition with the Aqua Cutter protected the building’s structure, which was GPS-monitored to the nearest millimetre and ventilation and gas monitoring systems maintained a safe working environment throughout.
Aqua Cutter 710V in action, delivering vibration-free concrete removal with millimetre accuracy beneath Merivale Mall.
Project outcome
The project was completed safely, on time and within budget. Stage 3 was delivered faster than expected and all noise and water management requirements were met.
The demolition maintained the structural integrity of the building and the client received high-quality, reliable outcomes that supported their wider construction programme.
Stage 3 matched the combined volume of the first two stages and was completed in just seven days.