Intensive Green Roof

Podium Deck, Deckdrain - Mei Foo Rail Station, Hong Kong

Client Kowloon Canton Railway Corporation

Kier Zen Pacific

Consultant Hyder Consulting

Deckdrain Drainage Geocomposite




– Easy handling, transportation and installation
– High performance drainage layer replacing drainage stone and pipe
– Enhanced noise protection
– Reduce load on podium deck
– Cost effective

Project Description

Mei Foo Station was constructed inside the Mei Foo Park and is part of the development of Hong Kong’s West Rail Metro line. This unique design achieved a complete integration with the existing park by incorporating a landscaped station roof and innovative rooftop parkland facilities for the public in this densely populated area.

KCRC won a British Construction Industry Award for ‘International Project of the Year’ and Kier won the ‘International Performance of the Year’ Quality in Construction Award for this project.

The Challenge

The residents wanted a podium deck finished with an intensive green roof to restore the park to its original state following the construction of the new underground station.

The design required a cover soil between 1 to 3m deep to sustain tree growth. Being a monsoon area the rainfall intensity is high, reaching 380mm/hr. The large run-off area from both hard and soft landscaping required a design with a high capacity, light weight drainage solution that could withstand construction loads.

The Solution

The initial specification was a 12mm geocomposite drain which would cover the whole surface of the roof. As the site developed, final levels and drainage routes were agreed and ABG was asked to check the overall capacity of the system at monsoon level flows.

ABG technical department calculated that the specified 12mm geocomposite would not offer the flow capacity required and proposed a higher capacity geocomposite drainage layer.

ABG manufactured and tested the bespoke Deckdrain 2700S drainage geocomposite under simulated site conditions to prove suitability for these high loads and flows. After extensive testing showing an in-plane flow capacity of 3 l/m/s at 3% hydraulic gradient under 20kPa soft platens (for soil load intrusion), Deckdrain 2700S exceeded the calculated value of 2.6 l/m/s. The Deckdrain drainage layer was quickly, easily and safely installed.

Deckdrain drainage geocomposite comprises a HDPE core with a high performance filter fabric fully bonded to it. The core forms an open void through which water can freely flow, whilst the geotextile filter fabric allows water entry to the void whilst controlling the ingress of particulates. In addition, Deckdrain enhances the noise suppression from the underground commuter traffic.

ABG Deckdrain geocomposite underneath the growing media on the Intensive Green Roof

The ABG Service

ABG Technical assisted with calculations and specific design for this site. An engineered bespoke geocomposite was manufactured for this project and delivered on time for a rapid and successful installation.

Contact ABG today to discuss your green roof or podium deck project specific requirements and discover how ABG past experience and innovative products can help.

Additional information