GREEN BUILDING FACTS

The SKY is the Limit

Green Roofs have become an important component of sustainable urban development in the last 30 years. Growing environmental awareness and the striking economic and ecological advantages are the driving forces for their popularity. At present, Green Roofs can be found in nearly all big cities around the world, benefiting the urban environments and their inhabitants.

GREEN ROOF TYPES

There are two main utilization options for Green Roofs: One, as a wonderful roof garden with a pleasant view for the owner; the other, an undisturbed habitat for flora and fauna within grey city centres. Both variations provide a broad range of private and public benefits. Deciding on which utilization to focus is crucial and has to be considered as early as the planning stage. In addition, the maximum load bearing capacity, maintenance, plant selection, substrates and the expense budgeting must correspond with the desired Green Roof type.

Extensive Green Roofs / Low Maintenance Green Roofs: Extensive Green Roofs are well suited to roofs with little load bearing capacity and sites which are not meant to be used as roof gardens. The mineral substrate layer, containing little nutrients, is not very deep but suitable for less demanding and low growing plant communities. Sun, wind and drought are additional stress factors for plants on buildings. Drought-tolerant plant communities, such as, those found in dry mountain environments, coasts, semi-deserts or dry meadows, are visibly adapted to the natural extremes of the local conditions and are preferred species. Mixtures of mosses, succulents, herbs and grasses create pleasant plant communities.

Intensive Green Roofs / Roof Gardens: Lawn, perennials, bushes and trees are possible on intensive Green Roofs. Walkways, benches, playgrounds or even ponds can be established as additional features on the roof. There are no limitations in design and individuality, but a few things have to be considered. The intensive Green Roof system build-up and the selected plant communities have to be harmonious with one another. In addition, the amount of maintenance of Intensive Green Roofs is higher than on Extensive Green Roofs and permanent irrigation and fertilization have to be ensured.

ADVANTAGES

Sustainable Land Use: New residential areas and new transportation routes are constantly being developed at the cost of the environment. Landscaped roofs can help reduce the local impact on nature. They act as “stepping stone biotopes” and give plants and animals a replacement for their natural habitat. Birds, wild bees and butterflies can all find nourishment and shelter here and create a lively ecosystem. Even endangered species can relocate to the green roof.

Natural Storm Water Management: Green roofs make a key contribution to flood protection. Depending on the type of construction, between 50 and 90% of the precipitation that falls on these rooftops is retained and returned directly to the water cycle via the process of evaporation. The excess rainwater is filtered and drained off with a temporal delay. This leads to reduced stress on the sewer system during the year and at peak flow periods.

Cite Climate: During the summer months many cities become true “heat islands”. It is the increasing numbers of houses and the waste heat from traffic, industry and heating systems that are responsible. Landscaped roofs can reduce the levels of excess energy through absorption and the evaporation of water, and can thus make the city climate more bearable. At the same time dust and toxic particles are filtered out, leading to massive improvements in the air quality.

Protection for the Waterproofing: “Naked” flat roods stand unprotect against weather conditions, UV-rays and mechanical strains. Over the years, the roof waterproofing starts to experience material fatigue, cracking and leakages. With green roofs, a natural buffer is formed against the weather and other environmental effects. The lifespan of the waterproofing can increase by as much as double.

Reduce Energy Costs: As a natural “coat”, landscaped roofs can lead to marked improvements in a building’s energy balance. House owners choosing to incorporate green roof systems will find that they quickly pay for themselves due to the resulting reduction in heating costs. They are also good for the environment as a whole, contributing to a reduction in the household’s CO2 emissions. During the summer months residents will also profit from the cooling effects of the green rooftop.

A Free Plot of Land: Landscaped roofs can be used for a range of purpose: for private rooftop gardens, to prestigious green areas on company buildings, to public parks. And the real highlight – rooftop gardens do no incur additional property costs. Both the panoramic views over the city’s rooftops and the special atmosphere are also part of the concept. Rooftop gardens improve living and working environments and provide natural surroundings in the immediate vicinity.