Defeating the ‘Heat Island Effect’

Defeating the ‘Heat Island Effect’

“Rooftop gardens not only benefit building owners, but also society at large.”

Eco-friendly building practices are no longer a gratuitous extra on a building plan. Many countries now see sustainable building as a responsibility, not a choice.

For example, France recently passed laws to ensure all new commercial buildings have solar panels or green roofs. And Switzerland and Toronto insist that where practicable private houses include green roofs.

So why is everyone clambering over this age-old concept?

The payoffs are real – not just for the building owner, but for whole societies and possibly even the entire planet.

At a micro level, the comfort and value of each building is enhanced due to thermal and audio insulation, making for quieter and more stable working environments. And most green roofs retain (and filter) rainwater, which has a direct pay-off in reduced utility bills.


But the gains for the individual building owners pale into insignificance next to the collective gains to society at a macro level.

As buildings absorb solar energy, they radiate heat, pushing up the ambient temperature. One building won’t have much effect, but imagine the impact of an entire city, with thousands of these heat-pumps warming up the atmosphere.

This urban temperature rise is known as the “heat island effect” and is exacerbated by the lack of vegetation (desertification). Remember those leafy tree-lined avenues we walked down as kids. That was no illusion, as the trees mitigated the effects of surrounding buildings.

So green roofs not only breath life into the city – filtering air and pollutants – they can also mitigate the heat island effect (and decrease global warming?).

Green Roofs fall into three broad categories:

  • Extensive; 75-125mm in depth lightweight and suitable for grasses, mosses succulents and herbs.
  • Semi-Intensive; 125mm-180mm suitable for small shrubs, perennials grasses and sedums.
  • Intensive; 180mm-600mm+ suitable for Perennials, lawns, Shrubs trees and rooftop farming

These days savvy investors factor “Green Ratings” into their returns. It’s extremely bankable, reducing wear and tear, bolstering rentals, improving working conditions, and improving resale value. And top that off with the knowledge you’re taking steps to reverse global warming.

This is arguably the first time in our architectural history that our buildings are designed with our grandchildren in mind. Green roofs allow us to ‘paid it forward’.


If you’re planning a Green Roof for your building it’s imperative that you get your waterproofing and insulation right.

The area is likely to be constantly moist, and any imperfections in the waterproofing will act as a magnet for water to find its way inside.

Be warned! Any attempt to replace or repair the integrity of the roof later is likely to be burdensome and costly!

So make sure it’s designed well and installed properly by qualified tradesmen.

Neuchatel NZ draws on decades of development in harsh European climates to bring you some of the most technologically advanced solutions for your Green Roof.

We’ve worked on projects for residential homes as well as landmark projects such as Aotea Square (atop the council carpark), Kelly Tarltons, several buildings in Auckland University, BNZ Tower (Queen St), ASB Tower (now the council’s head office), and even Princes Wharf.

The main products we use are:

  • Neuchatel Mastic Asphalt 20 mm thick robust and does not need a protection layer. Very good in all situations, long lasting and would be our first preference.
  • Torch on or cold-applied membranes are welded on site and are two or three layer anti roots systems. They also need a protective layer.

We’d love to share our ideas and experience with you, so feel free to give us a call or email any time.

For the last 100+ years Neuchatel has been protecting tens of thousands of surfaces from deterioration caused by heavy machinery and the elements. In this time they’ve refined their products and services to be more durable, environmentally friendly and affordable – especially for large scale projects