Heat Emissions from Top Floors of Multi-storey Car Parks with and without Rooftop Gardens

Assoc Prof Jamus Jerome Lim asked the Minister for National Development (a) whether HDB has made a study on the amount of heat emission from top floors of multi-storey car parks (MSCPs) that have parking lots; (b) whether gardens located atop such MSCPs emit less heat; and (c) what are the practical limitations that inhibit the conversion of MSCPs with underutilised upper decks into garden spaces.

HDB multi-storey car park (MSCP) rooftops are meant to provide unsheltered parking spaces. As part of greenery intensification efforts under the Green Towns Programme, MSCP rooftops that are not heavily used for parking are converted to extensive greenery and community or allotment gardens via the installation of the Prefabricated Extensive Green Roof Tray System, if found suitable. Studies by HDB have shown that this system can potentially mitigate heat gain by reducing surface temperature by an average of four degrees Celsius, as compared to a bare concrete surface.

Not all HDB MSCP rooftops, even if not required for parking, are suitable for conversion to greenery or gardens. The feasibility of conversion depends on considerations, including structural load, the availability of electricity and water supply, potential disamenities to residents, whether retrofitting can meet fire safety standards and development plans for the area.

Besides greenery or gardens, MSCP rooftops could potentially be put to other uses that benefit the community. We will continue to study approaches to make good use of our HDB MSCP rooftops.