Agenda Reports Pack (Public) 15/10/2012, 19.00 - Meetings ...

►►►Reducing air pollution as the vegetation on green roofs helps to filter outdust and smog particles. Nitrates and other airborne pollutants areabsorbed out of the air and rainfall and bound in the soil.Protecting the roof. It is a common misconception that a green roof candamage the roof structure. In fact a green roof can significantly increasethe life span of the roof. Temperature ranges on a standard roof can bevery wide with temperatures reaching 80°C, whereas on a green roof theywill reach about 25°C.Noise reduction. The sound insulation benefits of green roofs will varydepending on water levels, but they can reduce reflective sound by up to3dB and improve sound insulation by up to 8dB.2.15. The main disadvantage of green roofs is the higher initial cost. However the TaskGroup heard that these costs can be off-set by savings in other areas, such asground level storm solutions and energy demand. Whilst it is not within the remit ofthe Task Group, a discussion did take place over the potential for abuse of greenroofs. In particular there was a concern that some applicants may seek toincorporate green roofs as a way of circumventing the rules in relation to roofterraces. The Task Group felt that this was something that should be considered inmore detail by the planning department.2.16. The Task Group were impressed with the potential of green roofs and heard thatbetween 150 to 200 hectares of green roofing could be generated in London eachyear. It was highlighted to the Task Group that the green roof at Westfield couldabsorb up to 90% of rainfall on their area. In addition, the Task Group heard how theLondon Borough of Islington has retrofitted some of its municipal offices with greenroofing.Recommendation Four: Green RoofingIt is recommended that the Council approach the Department for Environment Foodand Rural Affairs (DEFRA) to enquire about the availability of funding for a pilotprogramme using financial incentives to encourage the development of new orretrofitted green roofs on pre-selected sites.2.17. As noted at the start of this report Thames Water records show that almost 700properties suffered the effects of flooding over the last 10 years; all of which wereassociated with heavy rainfall. Most of these have been basement properties. TheTask Group believe that basement properties are the most at risk from sewer,groundwater and surface water flooding. As a result the Task Group felt any personwishing to apply for a basement extension should be encouraged in the strongestpossible terms to install SUDs. In addition it was also felt that any person wishing toapply for a basement extension, given the substantial evidence that such extensionsare the most at threat from flooding, should be required to submit a more detailedflood risk assessment. Such a flood risk assessment should include anacknowledgment that the applicant understands the potential flooding risk to abasement extension. In addition it should require them to submit what steps theypropose to take to protect their property and the surrounding area due to the impactflooding can have on adjacent properties.2.18. The Task Group noted that Thames Water, as part of their sewer flooding alleviationin the Counters Creek catchment area, were undertaking a number of flooding local- 20 -Page 179