While more skyrise greenery has appeared in Singapore, many building owners are also holding back due to high retrofitting and maintenance costs.
Now, a scheme that has been underway since March is helping to tilt the balance further towards greenery.
Almost 40 organisations such as hospitals, shopping malls and corporate offices have come on board the National Parks Board’s Skyrise Greenery Incentive Scheme, which encourages the installation of green roofs or green walls on existing buildings.
A school, Kuo Chuan Presbyterian Primary, has also tapped the scheme for its S$70,000 rooftop garden, half of which was paid by NParks, on what used to be an empty concrete space.
“Many of the building owners … have recommended to other organisations to come onboard, and the take-up rate is increasing,” said NParks Deputy Director (Horticulture & Community Gardening) Ng Cheow Kheng.
“The benefits that they’ve enjoyed include the lowering of ambient temperature (and) reducing of noise.”
But only 11 of the 39 beneficiaries have used the scheme’s incentives for vertical greenery, with building owners citing high installation and maintenance costs as the main deterrence factor.
A green wall typically costs from S$1,000 to S$1,500 per square metre to install, or 10 times the amount needed for a rooftop garden.
The latter has its detractors, too, as some buildings are unable to withstand the heavy weight of a garden, while soil crumbling could leave the surrounding areas dirty.
So the search is on for more efficient alternatives, with a collaboration now between the National University of Singapore’s School of Design and Environment and Japan’s Suntory Midorie offering some promise.
This effort to research and develop vertical greening systems here will look at how these can be made more sustainable and affordable.
For instance, the environment greening business has created a urethane-based, spongy gardening material called Pafcal that serves as a substitute for soil, and it is hoped the technology could be commercialised here.
Professor Heng Chye Kiang, dean of NUS’ School of Design and Environment, explained: “It’s soil-less, it has very high water-retention capabilities, and so it’s essentially clean.
“At the same time, being in a new environment and tropical climate, how does it work here, what kind of plants will best work with this medium? These are things that we need to look into.”
Success in this and other fronts would then attract more building owners to take the green route up.
