INTENSIVE GREEN ROOFS IN THE LANDSCAPE To provide a comprehensive treatment and management of surface water, Intensive Green Roofs should be seen within the wider landscape. As source control elements, Intensive Green Roofs prevent runoff from being generated and becoming a problem further along the line. Below, opportunities for green roofs have been identified on a local scale – where roofs are not too steep and are of a certain size (in order to make it economical and achieve effects) there is potential to incorporate them to reduce surface water flows in the area.
CASE STUDIES Bridgewater Green Roof, Somerset
Intensive & Extensive Green Roof, Canary Wharf, London This report quantifies the energy savings from reduced heating/cooling demand due to the green roof. During the summer months the temperature remains at a comfortable level, the ventilation system is now not required to operate. In winter months, heating has become redundant. Saving in electricity consumption is estimated to be approximately 25,920 Kw per year. www.goo.gl/3wzgyz
Great Ormond Street Hospital, London The hospital has taken a creative approach to the use of limited outdoor space on this very constrained urban site. By accepting the impossibility of patient usage (because of the location of the space) this problem has been turned into an advantage: staff have a secluded space of their own where they can ‘switch off’, away from their patients, in a relaxing, fun environment. http://goo.gl/lYRnsg
EDUCATION In highly dense urban environments, accessible green roofs can provide a safe and convenient outdoor learning environment that not only gives access to natural habitats but can also increase focus and wellbeing of pupils/students.
COSTS & MAINTENANCE
FEASIBILITY
While instalment costs are high at £100-140/m2, IGR can increase the lifetime of a roof by up to 3 times compared to conventional roofs. They also have the benefit of not requiring additional land. Maintenance depends on the vegetation and can be similar to that of parks or gardens. Residential, Industrial, Retrofit possible. Only on flat roofs. Plants should be carefully selected to minimise irrigation and fertilisation needs. Intensive green roofs need strong roof structures due to their higher weight.
INTERVENTIONS TOOLBOX
This report investigates the whole life costs of a living roof (extensive green roof) in Somerset. It compares costs of an exposed roof, a sedum roof and a biodiverse roof and finds that the biodiverse roof achieves the best financial and non-financial results, due to a longer life time and insulation benefits. It has the greatest benefits for ecology. Added insulation effects of biodiverse and sedum living roofs will save approximately 4.9t of CO2 per annum. www.goo.gl/MFK4b6