Green roofs
A green roof is a vegetated cover or a permanent rooftop planting system covering a significant portion of a building’s roof. They mitigate stormwater run-off, reduce the urban heat island effect and increase biodiversity.
There are two main types: extensive and intensive.
Extensive green roof:
- Shallow layer of substrate or soil (20 to 150 mm)
- Low-growing stress-tolerant plants such as succulents, grasses and wildflowers
- Requires little to no maintenance and impose little weight on the building structure.
Intensive green roof:
- Deeper layer of substrate or soil (150+ mm)
- Variety of plants, vegetables, shrubs and even trees can grow
- Can be a habitat for wildlife
- Needs frequent maintenance like a normal garden.
Rooftop gardens
A standard rooftop garden has fewer planted areas than a green roof. Green roofs have substrate (or soil) covering the majority of the roof.
Rooftop gardens have plants in some sections of the roof. Edible gardens or shrubs also may be planted in containers or pots, rather than into soil on the roof itself.
Green walls and facades
A green wall is vegetation planted on the external side of a building. Most green walls are vertical hydroponic systems, with plant roots and soil attached to the wall.
A green facade typically features climbing vegetation planted on the ground or in raised planters growing up a trellis structure. Facade greening usually costs less than a green wall.
Wall or facade greening – as seen on our Council House 2 building – lowers a building’s temperature by shading it. It’s particularly useful for buildings facing the north and west.
Step by step guide to developing your green roof, wall or facade
Use the Growing Green Guide to design and develop your new green wall, roof or façade. It contains technical information about design, planning, construction, installation and maintenance.
It also includes some great case studies of green infrastructure on roofs and buildings throughout the city.
Our urban nature planting guide will help you find the right plant for your growing conditions.
If you are using planter boxers, pots or planting climbers: Find plants for pots and planter boxes.