There are three types of green roofs:
1. Extensive Green Roofs – designed for environmental solutions
- 3- 6″ of light weight growing medium.
- low-maintenance ground-cover plants.
- ideal for large flat-roof buildings and apartments.
- suitable for low-sloped residential roofs and retrofits.
- desert grasses and succulent plants.
- after one year, they do not require watering.
- annual spring weeding of tree seedlings & weeds – brought in by birds and wind.
2. Intensive Green Roofs – also known as rooftop gardens
- 8-12 inches, or more, of growing medium.
- fully landscaped roof top garden.
- require regular maintenance -similar to an at-grade garden.
- diverse plants and trees can be planted (avoid plants with invasive root systems).
- walkways, railings and lighting.
- parks, playgrounds or vegetable gardens are possible
3. Semi-intensive Green Roofs – elements of both extensive and intensive systems
- Semi-intensive roofs, combinations of both extensive and intensive green roofs, are typically adopted to harness both the environmental benefits of a green roof, as well as a diverse garden within a manageable maintenance budget.