Background It is generally accepted that climate change is happening. Public awareness of this reality and its potential effects is heightened by the increasing occurrence of extreme weather events. In July 2007, England experienced widespread flooding, which focused attention on the need to plan and adapt buildings, in particular, to a changing climate. Local authorities need to start adopting more stringent controls through their planning departments to reduce the impact of new and existing buildings on the environment. Green roofs – roofs covered with vegetation - are considered an innovative sustainable technique which could form part of a climate change adaptation approach. They can: help insulate houses better, reducing energy consumption; absorb rainwater and improve storm-water overflow problems; help lower urban air temperatures and mitigate the ‘Heat Island Effect’; and increase the absorption of CO2 in urban areas. They also provide additional benefits such as improved aesthetics of built-up areas and additional habitat for wildlife. Objectives The GRACC project aimed to address climate change by increasing the quality of green roofs. To achieve this overall objective the project planned to deliver the following sub-objectives: spread knowledge and experience relating to green roofs, through a UK good practice code, with associated standards and guidance develop a supplementary planning policy on green roofs for local authorities work with ten local authorities and/or public agencies to implement the supplementary planning policy work with the European Federation of Green Buildings (EFB) to spread good practice develop a pan-European green roof code in collaboration with EFB identify possible barriers to uptake of green roofs and provide solutions encourage adoption of the green roof code through an Innovation Awards scheme that will recognise inspirational approaches to roof greening, including combination with other sustainable features, such as the installation of photovoltaic cells and Sustainable Urban Drainage (SUD) organise events to raise awareness of the code amongst construction professionals and policymakers, and for information sharing and good practice exchange build a publicly accessible library of 30 case-studies demonstrating the benefits of green roofs for meeting environmental and biodiversity targets. Results GRACC can be considered as a reasonably successful project having developed the first UK specific code of best practice for green roofs, together with supporting documents, and demonstrated effective engagement of a national body representing the roofing industry. The project’s work should support the use of green roofs which can be expected to reduce flash flood events. However, the project was unable to complete the development of a Supplementary Planning Document for local authorities or a pan-European green roof code for reasons largely out of its control. The project successfully developed a UK-specific Code for Green Roofs. The Code sets out minimum standards for the specification of green roofs that will help to address climate change. It specifies that the depth of substrate material used should be at least 80mm. This is essential to ensure sufficient water retention to help reduce temperatures in urban environments, reduce the heating and cooling needs of buildings and provide increased biodiversity value. The project worked successfully to engage the key stakeholders – particularly the roof contracting industry, but also local authorities and other government agencies - effectively in the elaboration of the Code. This should improve longer term acceptance and use of the Code and also helped raise awareness of the Code and green roofs more generally. However, an important lesson of the project was that this process needs time. The necessary extensions to the consultation period meant that there was no time in the project to pilot the Code as part of ongoing green roof installation. To further support the development of green roofs in the UK according to the Code, the project established, sponsored and advised on a Green Roof Award Category at the National Federation of Roofing Contractors (NFRC) annual National Roofing Awards. The project attracted over 20 high quality entrants for both the 2010 and 2011 awards, with prizes given to the winner and runner-up. It also produced the following set of supporting documents, mainly aimed at practitioners: a general guide to green roofs Habitats Action Plan Guidance - for local authority planning officers a DIY (Do-It-Yourself) Guide for amateur enthusiasts a Green Roof Guide for developersWork undertaken to deliver a suitable Supplementary Planning Document for local authorities was unfortunately rendered obsolete by government overhaul of the planning system towards the end of the project. Efforts to support the development of a pan-European code were also hindered by funding problems of the partner EFB. The direct environmental benefits of the project cannot be quantified as there is no record of the number of green roofs installed that have used the Code during development. However, the potential environmental benefits brought about by the project are numerous. The most important recommended environment design aspect within the Code is that the depth of substrate material used is not less than 80mm. This is essential to ensure the long term sustainability of the roof in terms of water retention and biodiversity value. The average annual water retention of green roofs with this substrate depth is at least 10% more than that of the standard sedum matting (substrate depth usually 30mm) that is commonly used in the UK. This increased water retention helps to further reduce temperatures in urban environments due to increased thermal mass (substrate depth) and the cooling effect of vegetation. The extra insulation provided helps to reduce the heating and cooling needs of the building, reducing the buildings energy requirements and greenhouse gas emissions (in line with the Kyoto Protocol, UNFCCC and Directive 2010/31 on Energy Performance of Buildings). Reductions in flash flooding events can be expected (supporting the aims of the Floods Directive) and the quality of storm water run-off will also be improved due to the substrate filtering capacity (in line with the Water Framework Directive/Urban Waste Water Directive). Greater substrate depths also provide opportunities for more varied planting and more micro-habitats, increasing space for biodiversity (in line with the Habitats Directive). An increase in the quality of, and number of green roofs installed in the UK as a result of the use of the Code will have a number of socio-economic benefits. The Developers Guide to Green Roofs produced by the project highlights the fact that properties featuring green roofs built to the principles of the Code are more sustainable and could demand higher rents, increase the value of the property, and reduce surface water run-off and drainage requirements (and their associated costs). Green roofs have been found to extend the life of waterproof membranes applied to roofs, reducing maintenance requirements and costs. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).