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Waiomu Residential Property – MagnumStone™


Project Details


JJ Mangan Contracting


Private Homeowner


GDC Consultants


Waiomu, Coromandel

Cirtex Regional Contact

Darren Clare

Darren Clare

Project Information

Wanting to build a new home in Waiomu overlooking the beautiful Firth of Thames, the property owners required a retaining wall to protect their flat section of land from a steep, forested area behind. A timber retaining wall had been proposed, but the owners preferred the classic feel of MagnumStone.

MagnumStone also offered added benefits. Made of concrete, it would outlast any timber wall. Its hollow core meant it would be easier to insert drainage into the system, plus there was no need for invasive excavation to insert the timber poles, as the MagnumStone blocks are simply dropped in place. Less machinery, labour, and time made MagnumStone more cost-effective than the timber option.


The tiered wall comprises eighty standard MagnumStone blocks with a 90° internal corner at one end. It is retained to a maximum height of 2.4 m, with the small return dropping down to only 0.6 m. MagnumStone End Caps were fitted to contain the drainage metal at each end and to keep the wall looking pristine.

This MagnumStone wall was designed as a gravity structure. Extenders, fitted to the base layer of blocks, allowed the contractors to build with a base-to-height ratio of only 40%. This meant less excavation for the property owner. They could retain the slope much closer to the forested area without encroaching on their flat land.


Once the area of land had been prepared, the 650kg blocks were easily placed with the aid of a small excavator. The extenders were also lifted into place, slotting into the back of each MagnumStone block. This ease-of-use installation method meant contractors JJ Mangan successfully built the wall within a week.

Saving time and money, while creating a stunning retaining structure that will last a lifetime, the owners can now build their dream home and enjoy watching the sunsets over the Thames coast.

The MagnumStone system provided the following benefits to the project:

  • A great looking retaining wall that will complement the new home
  • Maximised the amount of usable land
  • A low maintenance asset with a 100-year design life

Project Video

Products used in this Project