Green roofs in Mediterranean areas e Survey and maintenance planning Cristina Matos Silva * , In ^ es Flores-Colen, Ana Coelho Department of Civil Engineering and Architecture and Georesources, Instituto Superior T ecnico, University of Lisbon, Av. Rovisco Pais,1049-001, Lisbon, Portugal article info Article history: Received 21 May 2015 Received in revised form 16 July 2015 Accepted 28 July 2015 Available online 1 August 2015 Keywords: Green roofs In-service survey Maintenance planning Mediterranean area abstract This paper addresses green roof maintenance in Mediterranean areas. A field survey is presented, describing building and roof systems of eleven case studies in Portugal, anomalies, causes and mainte- nance actions. The most affected system components were the vegetation layer, followed by the drainage system, substrate and paths. All inspected green roofs have regular maintenance, mainly concerning gardening operations, but a large dispersion in terms of frequency and type of maintenance actions was identified. The study confirmed that some design recommendations were not followed, especially the ones associated with singular points, accesses and safety measures. In-situ results were then used to propose a maintenance plan, structured for each system component, corresponding service life predic- tion and type of maintenance action. The inclusion of the real needs of in-service green roofs in Medi- terranean climate, with specific requirements for irrigation and cleaning, led to a more accurate definition of the maintenance actions and their frequency. The responsible person for each maintenance action is indicated. That helps to minimize overall costs, pathology and risks. © 2015 Elsevier Ltd. All rights reserved. 1. Introduction Green roofs were long-established due to their ornamental value while other positive contributions of this constructive solu- tion have been neglected. In the last decades, green roofs have become more popular and various studies now focus on the ben- efits associated with this roof constructive solution, e.g., the critical analysis of Berardi [1] for a general review. This integrated system can help to achieve high performance buildings and sustainable built environments, since green roofs absorb rainwater [2], air [3] and noise [4] pollutions, provide additional insulation [5], low ur- ban air temperatures [6] and create a habitat for wildlife [7], among other local and urban benefits. In order to assure green roofs benefits, this constructive solution should be correctly designed and maintained along its life cycle [8]. This also helps minimizing risks, such as fire [9,10] and ensures the longevity of the constructive system [11]. Several technical documents define the need of accurate design and predict maintenance actions for green roofs. Most of them follow the recommendations defined in the FLL Roof Greening Guideline [12] from Germany, widely accepted abroad, e.g., UK [10,13], Canada [8,9,11], Semi-Arid and Arid West [14], France [15] or Australia [16]. Normas Tecnol ogicas de Jardinería NTJ [17] are also based on FLL with application to Mediterranean areas (Spain). These references identify the need of a maintenance plan for owners, users and building managers to assure the good in-service performance of a green roof. Some define regular maintenance measures of the roof [9], such as cleaning or watering. The need of distinct maintenance requirements in extensive and intensive green roofs is also referred [12]. However, a detailed maintenance plan, with a description of maintenance actions and their fre- quency, is rarely found in the literature, standards or guidelines. This situation does not help the dissemination of green roofs constructive solutions, since owners and decision-makers will not feel comfortable in choosing this constructive solution. Maintenance varies from one region to another according to the local climate [18]. Green roof technology in Mediterranean regions is not stabilized as in continental Europe or the US. In fact, popular misconceptions are commonly referred e.g. in Malta, Italy or France [19,20]. Particular specifications of Mediterranean climate, such as hot and dry summers and mild to cool wet winters, high wind and solar radiation exposures or irregular rainfall pattern, should * Corresponding author. E-mail addresses: cristina.matos.silva@tecnico.ulisboa.pt (C.M. Silva), ines.flores. colen@tecnico.ulisboa.pt (I. Flores-Colen). Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv http://dx.doi.org/10.1016/j.buildenv.2015.07.029 0360-1323/© 2015 Elsevier Ltd. All rights reserved. Building and Environment 94 (2015) 131e143