The Benefits Green Roof Systems
As we recently reported, green roofs are on the increase here in the UK and we think we’ll be seeing many more of these “living roofs” in future. Today we’re going to take a look at some of the benefits to building owners that can be achieved by installing a green roof. To begin with, we’d like to point out that green roofs are nothing new – mankind has been covering buildings with all types of locally available vegetation since prehistoric times. Buildings were constructed initially as a means of providing a rudimentary shelter from the weather and the environment and early builders innovated, using whatever was easily available for all parts of the building. We still see thatched roofs on homes in many parts of Europe, particularly here in the UK which features the most thatched roofs. A properly constructed thatch roof will easily last for 50 years and during this time, despite being covered in dead vegetation, the roof becomes a haven for wildlife and plants. Seeds that are blown onto the thatch, along with any seeds remaining in the thatching material (usually wheat, rye or a mix of both, maslin) begin to germinate and grow leading to many thatched roofs sporting a small lawn “toupé”!
Modern green roofs, however, have come a long way and are usually flat, the simplest form being created by spreading topsoil (or other growing media) on a flat roof and sowing seeds. With green roofs becoming increasingly popular, green roofing companies are being launched to specialise in providing a living roof to domestic and commercial building owners. With rapid developments in green roof technology, going green in this way offers many benefits to both building owners and the surrounding environment.
To begin with, research shows that a green roof can increase the average lifespan of the roof up to three times. A green roof can hold up to 80% of stormwater runoff which may help to prevent flooding and lessen the building’s impact on urban drainage systems. This is the type of benefit that has resulted in many cities and districts offering grants or incentives to those who opt for a green roof system.
With urban areas experiencing higher temperature averages than rural areas due to the lack of green space, the vegetation on green roofs enhances the microclimate by absorbing heat and reducing the temperature while enhancing humidity. As the plants on a living roof photosynthesize, they absorb carbon dioxide and release oxygen, improving the surrounding air quality. Green roofs also absorb harmful gases (like nitrogen oxide and sulphur dioxide) and help to break down the poisonous gases released by vehicles and industry.
A green roof will keep a building cooler during the summer months, reducing the need for air conditioning yet acts as an insulator during cold weather, often reducing heating bills by more than 10%. The substrate and vegetation (and the air locked within it) combine to act as sound insulation with tests clearly showing a noise reduction of up to 50dB. A green roof can increase the efficiency of solar panel systems too by keeping PV panels cooler and helping to maintain an ambient temperature of 25°C which is needed for maximum energy absorption.
Green roofs are aesthetically more pleasing and provide some much needed green space in urban areas and provide rich habitat for small insects to breed within the urban environment.