As the name implies, green roofs are environmentally-friendly roofing systems that allow for plants and vegetation to be grown on top of buildings with flat or slightly-sloped roofs. These roofs are growing in popularity due to the environmental benefits these roofs can provide such as reducing a building’s energy consumption, providing habitats for local wildlife, and by helping to provide clean air to urban areas. However, if you are considering a green roof for your home or building, you may be wondering what green rooftop designs are available. Generally, green rooftops fall under the designations of extensive, intensive, and semi-intensive. To help you decide which type of green roof may be best for you, here is a quick overview of the traditional green rooftop design options.
Extensive roofs are perhaps the most common type of green roof available. Extensive green roofs consist of 3-6 inches of a lightweight growing medium and low-maintenance vegetation such as desert grasses, succulent plants, and sedum vegetation. Extensive roofs are popular due to the fact that they are light and are suitable for many buildings including certain sloped residential roofs. After the first year, extensive roofs do not require watering, and they require little maintenance outside of annual weeding. Extensive roofs are mainly chosen for their environmental benefits as they are not suitable as rooftop gardens.
Alternatively, intensive green roofs- also known as rooftop gardens- are primarily used on larger buildings with rooftop access. These roofs are much heavier and require much more maintenance as they generally consist of at least 8-12 inches of a growing medium as well as plants that you would traditionally expect to see in a ground-level garden such as shrubs, flowers, and even trees. Intensive green roofs can even include community features such as walkways, playgrounds, and vegetable gardens. These roofs require as much maintenance as a ground-level garden.
Semi-intensive green roofs (sometimes also referred to as hybrid green roofs), are a combination of extensive and intensive green roofing. These roofs combine the best features of both intensive and extensive roofs by providing a wider range of plants than extensive roofs while requiring less work than intensive roofs. The weight and maintenance requirements of hybrid roofs fall somewhere between extensive and intensive.
Ultimately, the type of green roof that will be best for you will depend on a variety of factors including your budget, what your building can support, and how much maintenance you are wanting to put into your living roof. Contact us for additional information on green roofs as well as for advice on choosing a green rooftop for your building.