A garden on the rooftop has many advantages in an urban environment, including:

• Improvements to the surrounding microclimate due the photosynthesis of the plants consuming carbon dioxide and producing oxygen; the much cooler roof surface and the moisture given off by the plants provide obvious benefits.
• The increase in thermal mass stabilises internal temperatures.
• A thicker roof structure reduces noise transmission.
• Retention of 50% to 70% of rain water, resulting in less site runoff.
• Absorption of dust and other pollutants.
• The provision of a habitat for birds.
• Aesthetically pleasing, particularly in urban living environments without a conventional 'back yard'.

There are basically two types of planted roofs:

• Extensive (up to 100 mm of soil)
• Intensive (greater than 500 mm of soil).

In both cases structural engineering design and specialist construction needs to be undertaken to ensure that the system will work.

In domestic urban environments the extensive system is most likely.   With this system a range of plants can be considered, including succulents, native plants, native grasses, and herbs.  Larger plants are only viable in an intensive system or pots.  Urban Green Living can design the specialist  requirements for rooftop gardens.