Sedum roofs include any roof surface lined with plants rather than traditional roofing materials. Sedum roofs are considered a type of extensive green roof, which includes roofs planted with small shrubs and flowers that are largely self-maintaining. They serve as an economical and easy-to-install alternative to intensive green roofs, which are designed to provide an elaborate park-like setting on the roof of a building. Sedum roofs not only serve as added green space in urban areas, but also offer a number of environmental benefits to building occupants and the community.
To create a sedum roof, contractors start by installing traditional roof framing and sheathing. These materials are covered by a waterproofing membrane, which prevents moisture from entering the structure. Simple frames are used to create compartments, or planting beds. Each bed is filled with some form of planting medium, which may include soil, gravel, or vermiculite. Small shrubs, flowers, and grasses can then be added to the planting medium.
Some companies also sell pre-manufactured kits that allow users to easily create sedum roofs. These kits include frames to support the planting beds, as well as mesh membranes equipped with a planting medium and seeds or young plants. Some also include built-in drainage systems to ensure proper waterproofing and moisture protection.
These green roofs are named for the plant genus Sedum, which includes many species of hardy, green plants. Many of these species are largely self-sufficient, and can live solely on rainwater. In certain climate zones, small sprinkler systems may be required to support these roofs.
Like other types of green roofs, sedum roofs provide many benefits to occupants. The plants and plant medium act as a layer of insulation, which helps to regulate the temperature within the structure. It also helps to improve energy efficiency and cut heating and cooling costs year round. Added green space also improves air quality and helps to reduce the phenomenon of urban heat islands. These roofs also serve as an attractive space when viewed from higher elevations, or from access points on the roof itself.
Depending on the size and weight of the sedum, these roofs may require additional structural framing support, which could increase building costs. They may also pose a challenge to building owners in terms of maintaining effective drainage channels. Finally, sedum roofs tend to cost more than traditional asphalt or rubber roofs on average, and may not fit every project budget.