Tucked away on the roof-extension of a beautifully renovated Auckland villa is a system that could be the answer to the country’s stormwater and quality-of-water-woes.

With the copious amounts of rain in NZ, it is mind-blowing to hear about low-water levels in reservoirs, and towns being put on water restrictions when approximately 101 billion litres of storm-water is lost through leaks and wastage.

The designer of this kitchen-dining-living room extension had to think outside the box when plans resulted in a larger-than-normal proportion of the site being occupied by the building. This would run the risk of putting too much pressure on the public stormwater system during periods of heavy rain; leading to surface flooding. A solution was found with the Viking Roof Garden System. 

The soil of a Viking Roof Garden system acts like a sponge to absorb, delay and slowly release storm water as well as acting as a filter to purify the water. The oxygen produced by the planted vegetation helps to insulate and shade the building, reducing the energy consumption of the building and greenhouse gases. It also minimises the exposure of the waterproofing membrane to climatic extremes, increasing the life of the roof and its long term performance.

With approximately 120m² of roof garden surface area supporting an average of 500mm deep of growth medium, the system takes a huge amount of pressure off public services by providing an absorbent catchment facility of approximately 60m³. This will feed rain water into the storm-water system in a more controlled manner than would be the case if a sudden downpour pelted the impermeable surface of a traditional roof.

In addition, some of the water from this roof will feed into a grey-water tank used for watering gardens, cleaning cars and flushing toilets. This decision has led them making a considerably large, green, eco-friendly footprint with the use of a full Viking Roof Garden System.