Green roofs benefit the environment, help companies achieve sustainability targets and payback times are getting shorter, says Atmos Consulting.
The pressure is on building developers and occupiers to make sure their buildings are energy efficient and green roofs are proving to be an effective tool in reducing carbon footprints. 
Environmental consultancy Atmos Consulting says green roofs are suitable for new and existing buildings. These roofs are partially or completely covered in vegetation, planted in substrate over a waterproofing membrane. They offer a wide range of environmental and financial benefits, often paying for themselves over a short period of time.
According to research reviewed by Atmos Consulting, green roofs:
• Insulate buildings, slashing energy costs. Recent studies show green roofs save 2 litres of fuel oil/m² per year.
• Cut the rate of heat absorption through the roof of a building by up to 84%, reducing its temperature and the need for cooling. This leads to further energy savings.
• Can be expected to last between 2.5 to 3.5 times longer than roofs made from standard materials, slashing roof repair and replacement costs.
• Reduce urban pollution levels. 1m² of grass roof can remove 0.2kg of airborne particulates every year. They can also store chemicals and pollutants falling in the rain that would otherwise go directly into drainage systems.
• Help companies and organisations manage excess water in storms by retaining 50-60% of the total annual runoff volume in an average development, and alleviate flooding issues by retaining 90-100% of the critical first hour of heavy rainfall. This reduces drainage costs.
• Provide excellent habitation areas for insects, birds and other wildlife, increasing local ecology/biodiversity.
• Contribute towards government-set sustainability targets ,br/>.
There are two main types of green roof. The first uses rolls of Sedum, a hardy plant, which can be easily applied to flat and slanted roofing. Sedum green roofs are cost efficient and the plants produce pretty flowers and require little moisture, making them easy to maintain.
A prime example of a Sedum roof is at Atmos Consulting’s award-winning and BREEAM accredited offices in Mold, north Wales (pictured).
Biodiversity/brown roofs aim to provide habitats for species living on the rooftop. They can contain flowers, ponds, wildlife towers for insects and animals to live in, and even trees. Biodiversity/brown roofs look brilliant and make great social/work spaces. However their development and long-term maintenance costs are higher than Sedum roofs. Biodiversity/brown roofs can also be very heavy, which can place load-bearing requirements on building structures.
Vicky Ward, Ecological Consultant at Atmos, is positive; “Green roofs have long been popular with companies that want to better the environment, and go a long way to achieving sustainability targets.
“Thanks to developing technology the payback periods are becoming much shorter, making green roofs a sound financial investment. We urge anyone developing new properties or renovating existing ones to consider them.”
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www.atmosconsulting.com
Atmos Consulting is an environmental consultancy, specialising in renewable energy, with offices in located in Scotland, England and Wales.