23rd
January
2012
Green roofs help companies achieve sustainability targets and payback times are getting shorter
Stewart Lowther, Managing Director of Atmos Consulting comments on how green roofs can help companies achieve sustainability targets.
The pressure is on building developers and occupiers to make sure their buildings are energy efficient and sustainable and, as an environmental consultancy, we are called upon to examine all aspects of development. So our team includes experts in disciplines ranging from drainage and ecology to, more recently, green roofs. We have employed a specialist, Dr Victoria Ward, to advise clients on their potential and one of her first jobs has been to review the market to establish beyond doubt the 'case' for giving serious consideration to green roofing.
Green 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.
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 our own award-winning and BREEAM accredited offices in Mold, north Wales.
Close up of sedum roof from Atmos' sustainable office in Wales.
The alternative is biodiversity/brown roofs, which 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.
According to the research we have reviewed, green roofs have potential for any new or refurbished building, they are certainly not the preserve of 'dyed in the wool environmentalists':
- Insulate buildings, slashing energy costs. Recent studies show green roofs save up to 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.
- Reduce urban pollution levels. 1m² of grass roof can remove up to 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 up to 50-60% of the total annual runoff volume in an average development, and alleviate flooding issues by retaining up to 90-100% of the critical first hour of heavy rainfall. This can reduce drainage costs.
- Provide excellent habitation areas for insects, birds and other wildlife, increasing local ecology/biodiversity.
- Contribute towards government-set sustainability targets (e.g. BREEAM assessments).
- Generate lots of positive publicity in the local press and trade magazines.
"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."
Contact us to find out more about our sustainability services.
Atmos will be exhibiting as green roof partner at the NHS sustainablilty conference on 14th February in London.
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