Green Roof

• Roof tops where landscape planting are incorporated are getting popular in recent years. Different countries or standards may have different definitions or names for this type of roof.

• In the context of Singapore, National Parks Board define Green roof as; Extensive green roofs are in general not designed for active recreational use. They are developed mainly for aesthetic and ecological benefits. Distinguished for being low in installation cost, lightweight (50-150$\frac{kg}{m^2}$) and with shallow mineral substrates, minimal maintenance is expected. Inspection should be preformed, at the minimum, once or twice a year. Plants selected are usually of low maintenance and are self-generative. Extensive systems can also be placed on pitched roofs of up to an inclination of 30°. They are common in European countries, especially Germany.

• A roof or deck onto which vegetation is intentionally grown or habitats for wildlife are established, including extensive, intensive and semi intensive roofs; roof gardens; biodiverse roofs; brown roofs; public and private amenity spaces.

Drainage Facilities

Types of Drainage facilities;

• Roof drainage outlets
• Interior piping
• Gullies or scupper drains at doorways and parapet walls
• Gutters
• Spouts
• Emergency overflows

Irrigation

The more intensive the roof, the more likely it will require artificial irrigation system is required. Requirement for irrigation depends mainly on the following factors;

• The planting layer’s water demands
• Water storage capacity of the green roof configuration (e.g. growing medium, drainage layer)
• Local precipitation patterns

Rainfall is the typical source of water, however complimentary irrigation options include hoses, sprinklers, overhead irrigation and automated systems that pump from some reservoir storage. The establishment of a need for an irrigation system, and the design of an irrigation scheme, should be in accordance with the principles of BS 7562-3:1995 Planning, design and installation of irrigation schemes – Part 3: Guide to irrigation water requirements. Standards relevant to the design of specific irrigation systems include BS EN 15099-1:2007 – Irrigation techniques. Remote monitoring & control system, BS EN 15097:2006 – Irrigation techniques. Localized irrigation hydraulic evaluation and BS EN 13742-1:2004 – Irrigation techniques. Solid set sprinkler system – selection, design, planning & installation.

References

1. CS E04:2010 Guidelines on filter, drainage and root penetration barrier layers for rooftop greenery
2. The GRO Green Roof Code UK Green Roof Organisation (GRO) - a body facilitated by the National Federation of Roofing Contractors (NFRC)