There are a considerable number of benefits to be gained by planting a green roof. These benefits can be categorised as environmental, societal, and economic.
Environmental Benefits
The first and most obvious environmental benefit of green roof planting is of course their visual appearance. They immediately soften the whole area around them – providing a visually pleasing, attractive appearance. If the buildings are in an urban area, the green roofs will immediately provide a much needed, colourful dose of nature to the environment, helping to cancel out the cold, harsh greys of the city. If the buildings are in a semi-rural location, the green roofs will enable them to completely blend in with the natural environment – making them appear almost invisible from a bird’s-eye view. There are even green roofs which are built in an undulating fashion – to imitate the contours of the landscape around them. This allows them to blend into the local environment even more – particularly in areas with rugged terrain.
The second most obvious benefit is greatly increased biodiversity in the area in which green roofs are planted, as the grasses, herbs, sedums, plants and trees provide a natural habitat for birds, butterflies and insects. Again, this is especially important in a city setting, where rich biodiversity will be in short supply.
In addition, green roofs also possess fantastic air purifying qualities. They add oxygen to the air around them, which is essential in urban areas like city centres, which suffer from poor air quality due to a lack of oxygen.
Green roofs also reduce temperatures in urban areas as they absorb the heat of the sun – rather than heat building up by bouncing back and forth off buildings. A city with a substantial number of green roofs can be around 3°C cooler than one without – helping to make a hot Summer much more bearable.
A green roof also acts as a buffer against excess rainwater, by delaying the flow of rainwater to the sewage system and purifying the rainwater at the same time. Rainwater runoff is also greatly reduced, as substantial amounts of rainwater will be absorbed through the plants. These benefits help to reduce the peak load on the sewage system and reduce the risk of flooding.
Societal Benefits
The foremost societal benefit of green roof planting is the increased feeling of well-being gained by people living and working in the area. The added greenery softens the whole area, reducing stress and helping people to become more relaxed – therefore improving peoples mental health. This greenery, if visible from a hospital setting, can even promote faster recovery times for patients – resulting in a shorter hospital stay – and thereby freeing up beds faster.
A greener environment also helps to bring people together – which has a positive effect on social interaction in neighbourhoods. Areas containing more greenery tend to suffer less from aggression, violence, and vandalism.
Additionally, people living or working in a building which hosts a green roof will also experience more peace and quiet – as a green roof acts as a sound barrier by absorbing sound. This will result in a substantially more stress-free environment.
Economic Benefits
A green roof immediately adds value to a building, as it will extend the lifespan of the roof, reduce energy costs, and enhance the buildings appearance by ensuring that it’s natural and sustainable. Green roof planting ensures that the roofing material is protected from the weather, such as rain, wind, sun and temperature fluctuations. This can double or even triple the life span of a roof – demonstrating that installing a green roof really does pay off.
Green roof planting will even benefit the use of solar panels on a roof, because as mentioned above, a green roof will reduce the roof temperature – allowing the solar panels to operate more efficiently and therefore reducing energy costs. This reduction in roof temperature will also reduce the temperature throughout the whole building, meaning additional energy savings by not having to use the air conditioning as much during Summer.
Green Roof Planting is Vitally Important
So, you can see that there are a multitude of benefits to be gained by green roof planting. It’s likely that you’ll already have known about some, but we have also addressed many that are not so obvious – but still incredibly beneficial. Green roof planting is more important today than ever before, as the continued growth of urban areas requires appropriate countermeasures to ensure that nature can still survive and even thrive, improving these areas for all.
Maintaining a Green Roof
A green roof is a considerable investment in the building project, so it makes sense to ensure the roof will thrive. During very dry periods, even drought tolerant planting will need additional watering if it is thrive. Very dry conditions may also lead to a loss of biodiversity as only the hardiest plants will survive. A green roof irrigation system will use drip irrigation line with a close spacing to add water to the roof area. The system would be automatically controlled with an irrigation timer and weather sensors. Water Regulations require a break tank to isolate the green roof irrigation system from the public water mains.
