Sustainable Landscape Design for Green Roofs: Living Beauty for Unused Space
Other European countries began to construct green roof systems as well, including Switzerland, where living roofs have been mandatory since the late 90′s, Austria, Sweden, Italy, and in some parts of the UK. Green roof construction has also began in the US as more developers, homeowners, and businesses see the widespread benefits of
Types of Green Roofing
Living roofs fall into 2 primary categories – intensive and extensive. Intensive roofs are the most similar to traditional, ground level gardens and generally have at least a foot of soil. These designs can support a variety of plant life, including herb and vegetable gardens, shrubs, and even small trees, but also require extreme structural support, easy access,and typically a great deal of maintenance.
Extensive roofs are much more common. Generally requiring just 2 to 4 inches of soil, these green roofs can be installed on most structures and usually feature hardy, self-sustaining sedum species that require very little work to maintain.
Installation and Maintenance
Green roof construction is somewhat similar to that of green walls, but rooftop systems require additional drainage and waterproofing features because of their location.
Structures with moderately pitched or curved roofs provide the best foundation because the slope allows proper drainage, but flat roofs as well as roofs with a steep pitch can work. An existing roof structure of any type may need re-enforcement before installing a green roof.
Sustainable landscape design for green roofs begins with waterproof membranes on the roof. One layer may be sufficient for a well-designed structure, but additional layers may be required to prevent leakage.
A drainage layer is installed to aid in moving excess water off the roof, as well as a root barrier to prevent plants from attaching to the roof. Soil medium, typically a nutrient-rich compost, is added before the vegetation is planted.
Maintaining an extensive green roof system doesn’t require much effort.The garden may need to be weeded occasionally or plants may need pruned.
Sedum varieties (a species of leaf succulent) are generally selected because of their ease of maintenance – they are low-growing, hardy plants that demand minimal watering and care. Large scale green roof construction requires the expertise of a landscape professional with sustainable design knowledge.
Benefits of Living Roofs
Green walls and roofs add aesthetic beauty to both commercial and residential structures, but also offer a number of environmental benefits. Besides protecting the ecosystem, green roofing also adds to the market value of the building, minimizes typical wear to the roof, and provides substantial savings on energy bills.
Benefits of green roof systems include:
- Protection from UV rays and acid rain, extending the life of your roof;
- Natural cooling that combats the urban heat-island effect and reduces the need for air conditioning;
- Reduced storm water runoff, minimizing the need for extensive piping systems and water treatment;
- Natural carbon sequestering (the natural process of balancing carbon dioxide in our atmosphere) with an undisturbed growing process;
- Better health for nearby residents and improved conditions for those within the building;
- Creation of natural, safe animal habitats to promote breeding and sustainability.
Aside from the initial costs, there are very few disadvantages to living roofs and green walls. Sustainable landscape design for green roofs can benefit everyone, as well as the environment.