A green revolution is taking root on Hong Kong's rooftops and, slowly but surely, is set to change the aerial view of the city.
Building owners and property management companies are waking up to the fact that sky gardens are the way to go if they want to cut costs and take a decisive step toward creating a greener urban environment.
One such example can be found atop the recently refurbished Prosperity Place office tower in Kwun Tong's Shing Yip Street. Conceived as a pilot project, it was laid out with the help of engineers and a landscape architect, and it is already proving a big hit with tenants, building services staff and visitors.
"This is our first step," said Stephen Chu, chief executive of ARA Asset Management (Prosperity), which oversees the building, along with six other commercial and office properties in Hong Kong. "It is not for show, we actually want to do something for the environment. We will now expand here where there is more roof to cover, and then move on to our grade-A buildings."
Chu explained that the practical advantages were already clear. The expanse of grass and other greenery would act as natural insulation, reducing internal temperatures on the top floor by around two degrees Celsius in summer. Power generated by a turbo fan and solar panel could light parts of the building. Rainwater collected in a 1,000-litre tank would cut consumption from the main supply and utility charges, which typically represent 10 per cent of the building's recurrent expenses, would fall by as much as 15 per cent.
Tenants now had somewhere to de-stress, grow herbs and, potentially, hold social events and barbecues.
"We are testing on a micro scale initially to see which ideas give best bang for the buck," Chu said. "There is always a cost-benefit analysis, but this is low maintenance, people buy into it, and the building management team is very enthusiastic."
According to Mavis Wong, ARA's senior manager for asset and investment management, the whole project had taken about three months to implement and cost HK$400,000. There had been a feasibility study to understand best practices from around the world and detailed planning with local engineers and consultants to test for loading, drainage and possible typhoon hazards. As a result, pebbles were glued in place and a risk management team devised clear policies for such things as bolting down furniture.
She expects to see the creation of "living" roofs gather pace. She did caution that it was easier to work with wholly owned properties, rather than strata-title buildings where multiple owners were involved.
Jan Wong, ARA's manager for investor relations, added that the company was committed to making a difference and minimising its carbon footprint in a densely populated area. There is, though, another aspect, since many overseas institutional investors now ask for evidence of green initiatives.