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Over the last two decades, major research have been made about green roofs, this article tries to raise more awareness on green roof components and its many benefits (environmental, social and economic) that are related with the green roof technology. This article also places emphasis on how green roofs works in different areas, their overall performance in reducing storm water and energy costs, and improving air and ecological performance. The benefits of green roof shows that it plays an important role in making cities more secure, sustainable and resilient to local climate change. However, huge construction costs, excessive renovation costs and roof leakages are the primary challenges associated with the application of green roofs. These challenges can be overcome with new cost effective green roof layout that can work successfully and efficiently in any area. Advanced amendments and traits of green roof application are also covered in this article.
International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online)
Vol. 7, Issue 2, pp: (106-112), Month: October 2019 - March 2020, Available at:
Page | 106
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CYPRUS, by Mersin 10 TURKEY
Abstract: Over the last two decades, major research have been made about green roofs, this article tries to raise
more awareness on green roof components and its many benefits (environmental, social and economic) that are
related with the green roof technology. This article also places emphasis on how green roofs works in different
areas, their overall performance in reducing storm water and energy costs, and improving air and ecological
performance. The benefits of green roof shows that it plays an important role in making cities more secure,
sustainable and resilient to local climate change. However, huge construction costs, excessive renovation costs and
roof leakages are the primary challenges associated with the application of green roofs. These challenges can be
overcome with new cost effective green roof layout that can work successfully and efficiently in any area.
Advanced amendments and traits of green roof application are also covered in this article.
Keywords: Green roof, Components, Benefits, Promotional policies, Advanced modification.
Climate change and urbanization are matters of modern interest. Due to speedy financial growth, urbanization is growing
in many countries which degrade the natural landscape as well as the close environment. These problems can be solved by
making use of green infrastructure strategies. The introduction of new urban development techniques such as rain
gardens, green roofs, and green partitions can help reduce the direct effects of urbanization and improve the environment
of an area. Green roofs are basically roofs that are planted with a distinct form of vegetation/plants on the top of a growth
medium (soil). The idea is to encourage the implementation of vegetation on the top of buildings to get multiple social,
economic and environmental benefits. A green roof commonly consists of several components, including vegetation,
substrate, filter layer, drainage material, insulation, root barrier and water proofing membranes. The placement of each
component of the green roof is very essential in order to get the best outcomes from the green roofs. Each component is
equally important and performs a very important role for the better overall performance of green roofs in an area. Due to
multiple benefits, green roofs are being applied in many countries. Research on the green roofs indicates several social,
environmental and economic benefits. Significant evidence indicates that green roofs can supply more than one benefits,
such as storm water management, depletion of heat in urban context, increase in urban plant life, small increase in wildlife
habitats, improvements with regards to the air and water quality and quality of life in an urban context, decreased energy
consumptions costs of buildings, decreased noise pollution, encourages recreational activities and increase in aesthetic
value in an urban environment. As a result of water quality enhancement, green roofs decrease the workload of the water
cure amenities in an area. Due to the above advantages, many countries begun to design green roofs on their buildings. As
the result of this more and more green roofs are established and designed day by day around the globe.
Planted roofs can improve the thermal environment in cities with the aid of decreasing solar absorption, Daily thermal
variation and annual thermal fluctuations. By providing large vegetated surfaces, they contribute to the improvement of
International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online)
Vol. 7, Issue 2, pp: (106-112), Month: October 2019 - March 2020, Available at:
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Research Publish Journals
thermal performance of the building (Eumorfopoulou and Aravantinos, 1998). Niachou A et al (2001) which observed
that the indoor temperature values in buildings with green roof are lower during the day, in order to support this finding,
they measured the roof temperatures of non-insulated buildings, with and without green roof. The end results shows that
the roof temperature of non-insulated building without green roof varies from 42 to 48 degrees Celsius whilst the
temperatures of the green roof upon non-insulated building are lower and ranging from 28 to 40 degrees Celsius. They
also concluded that the existence of large temperature variations due to the installation of green roof could lead to energy
saving potential.
A research to inspect the outcomes of rooftop garden on energy consumption of a five-storey commercial building has
been carried out in Singapore. The study was performed on three different types of roof which are exposed roof, typical
flat roof and rooftop garden with different stages of vegetation (low vegetation, medium vegetation and high vegetation).
The results of the study showed that the installation of rooftop garden on five storey commercial building can result in a
saving of 1 to 15% of annual energy consumption, 17-79% in space cooling load and 17-79% in the peak space load and
shrubs were found to be the most effective energy consumption in building
(Wong et al., 2003b).
Many research has established that different kinds of vegetation could provide unique thermal reduction measurements.
Large foliage development with mainly horizontal leaf distribution could give excellent thermal reduction (Barrio, 1998).
Those finding were supported by Wong et al. (2007) which indicated that the temperatures measured underneath
extensive greenery coverage were considerably lower than that measured underneath the groundcover with tiny leaves.
Lower temperatures were obtained under thick greenery while higher temperatures were obtained beneath sparse
vegetation or only soil, and green plants irradiated and reflected less solar heat (Wong et al., 2003).
Wong et al. (2003b) also conducted a simulation study to learn about the strength of energy consumption for different
types of roofs on a five-storey commercial building in Singapore. The comparison between rooftops that are without
vegetation, rooftops that are totally covered with turfing, shrubs and trees was carried out on that building. The result
revealed that shrubs were the most effective vegetation in reducing energy consumption in buildings while turfing has the
least reduction.
This article provides an overview of green roof technology and suggests how they have considerably contributed to
supply more than one benefits (social, environmental and economic) in urban areas. This paper reviewed global literature
from distinctive sources, i.e. peer reviews, research articles, books, case studies, conferences, technical reports, design
guidelines, project summaries and group discussions. A search of a number of different keywords for the green roof that
includes green roof technology, green roof components, green roof benefits, green roof policies, and a new combination
of green roof for a number of benefits. This assessment is giving an insightful overview of the green roof to the common
user to recognize the green roof technology. This overview additionally explains the components of the green roof and
their benefits in details. Many research has been stated to show the green roof benefits for storm water management and
improving the environmental performance in unique areas.
This paper gives an overview of green roof technology and shows how they have significantly contributed supply many
advantages (social, environmental and economical) in urban areas. This review paper differs from the previous review
works on the green roofs in phrases of quite a number of aspects. First of all, the idea of green roof is explored in a
holistic way in this review paper. The review initiates with a historical overview of the green roof technology with the aid
of theoretical basics and clear explanations. Each component of green roof is comprehensively described with their
benefits. Each benefit of green roof with the life cycle assessment is described in details, green roof promotional policies
of different countries as well as the research gap, the problems and technical difficulties that are associated with green
roofs are also described in details.
International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online)
Vol. 7, Issue 2, pp: (106-112), Month: October 2019 - March 2020, Available at:
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There are various kinds of green roof model established by way of research. Each model consists of simple aspects of
green roof which are plant layer, growing medium and drainage layer. For lengthy term environmental benefits, the
choice of each layer according to the region and climatic benefits is very important. Every aspect of green roofs is very
important and should be selected appropriately to achieve the most advantageous results.
Typical components of a green roof.
A. The most crucial and exciting part of the development of green roof is the selection of plant layer, which maximize
the green roof life. The fulfilment of green roofs depends on plant's health. With regards to the selection of plant, we have
to consider the geographic vicinity, rainfall intensity, humidity, wind and sun exposure. Depth of growth can additionally
determine the plant species we can use for green roofs.
Plants usually use for green roofs all around the globe.
Green roofs are the best storm water management practices in urban areas due to the fact that plant life and substrate
layers have capabilities to store a huge amount of water. As a result of this, the possibilities of flash flooding decreases in
city region.
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Vegetation/plants of green roofs, enhance the runoff water quality, air quality and decrease the heat waves in an area.
However, it must pointed out that the rooftop is not the ideal space for natural plant growth. Water is always a limiting
factor for rooftop environments. Similarly, building regulations restrict the soil depth. The soil additionally needs
essential nutrients to maintain overall performance of plant life. After thinking about most of these restrictions at rooftops,
the ideal plants/flowers to be considered for rooftops should have the following characteristics.
• Capability to withstand drought and excessive climate conditions.
• They should be easily available and economically friendly.
• They shouldn’t need frequent irrigations.
• They should have short and tender roots.
• They should have the ability to continue to exist under minimum nutrients conditions.
• They should require less maintenance.
More evapotranspiration.
Can lessen the heat island phenomena
It is very difficult that plants can have all of the above favourable characteristics, but significant progress have been made
for the selection of suitable vegetation for green roofs.
B. The growth medium layer may be known as the crucial layer because it directly affects the plant's growth and the
success of a green roof. Consequently, the standard choice of this growth medium (soil) should be necessary for the
success of a green roof. Most of the green roof benefits are directly correlated with the substrate of green roofs which
includes water quality enhancement, runoff reduction, peak flow reduction and thermal advantages. The growth medium
must have specific properties, i.e. mild weight and the high ratio of natural minerals that help for plant increase, but it isn't
always sensible that a substrate may have all preferred properties. Consequently, the general exercise is to mix the
different additives in growth substrate.
Green roofs growth mediums should have a low bulk density, because if it has a high bulk density it may collapse the
structure, especially in old buildings because the load restriction cannot allow the additional heavy weight to substrate.
Hence it is continually attempted to keep the weight of the green roof as little as possible. This can be achieved by adding
lower density inorganic material within the substrate.
The green roof water proofing membrane material should have high water holding capacity (WHC) because it helps to
minimize the peak runoff flow and helps to allow the plants survive under drought conditions. WHC can be increased by
increasing the substrate volume and depth.
Growing media of green roof should have high air filled porosity (AFP) because it helps the continuity of water under
rainy events and prevents the leakage of a green roof. An optimum substrate should stable and support the wide ranges of
the plant/vegetation. It should also be light weight and help plants to be able to withstand extreme climatic conditions.
C. A filter layer of green roofs is used to split the growth medium from the drainage layer, and stop smaller particles like
soil fines and plant debris from getting into and clogging the drainage layer. This is also called, geotextiles and are used to
provide higher continuity for water in the drainage layer. These filter fabrics have high tensile strengths and high water
permeability to flow water into the drainage layer.
D. An insulation layer isn’t always an obligatory layer on any roof. This sediment prevents water stored in the green roof
system from extracting heat in the winter or cool air in the summer. More insulation is usually required when green roofs
are applied on existing roofs in restoration or retrofitting projects. Depending on the design and type of the roof it should
be provided. However, it is placed above the waterproofing, as it further protects the membrane from condensation and
physical damage.
The biggest challenges for the drainage layer is the cost and disposal of drainage layer is a big issue for the drainage layer.
Hence, further research is needed for the selection of better cost effective and environment-friendly drainage layer.
International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online)
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E. The drainage layer could be very crucial for green roofs because it lets in the removal of excess water from the
substrate. In this manner, it reduces the weight on the building and possibilities of a collapse of building structure
additionally decrease. It also protects the water-resistant membrane and improves the electricity efficiency of the building
F. The waterproofing membrane is vital for the green roof to avoid the leakage of water on the roofs. Within the green
roof, because the moist soil and high moisture content increases the chances of leakages of green roofs. Therefore, a
waterproofing membrane is very essential for green roofs and care has to be taken while the selection of waterproofing
B. Reduction of surface temperature and thermal comfort are the two crucial capabilities of the green roof in an urban
context. Green roofs add thermal resistance to the building this causes the cooling of the building in summer and
additionally reduces the electricity expenses. Green roof vegetation and substrate absorbs fewer solar radiation than the
alternative types of roofs, hence also saving the money use for cooling
C. Green roof has potential to capture the harmful fine dirt particles from the air that could help to comfort for human
in highly developed urban areas. In urban areas, the air typically contains fine dust particles that make the urban
environment bad and uncomfortable.
D. Another benefit of the green roof is the reduction of the noise level. A green roof can act as a kind of sound
insulation. Closing off some level of noise from outdoors.
E. Green roofs additionally beautify the aesthetic of an area in addition to the natural world. Peng and Jim confirmed
that the green roofs play a crucial role to enhance the urban ecology, however it is difficult to measure in urban areas.
Numerous studies shows that green roofs are very helpful to reduce the habitat loss in the urban context. Green roofs also
promote the leisure activities in city areas. It promotes the wildlife by allowing them to be available in green areas. It
attempts to make impervious surface areas into natural green areas that can also add environmental benefits in urban
Despite the fact that green roofs are considered as a potential opportunity for pollution control and an attempt to retrieve
the natural hydrology in urban areas, the demanding situations which restrict their use still stay. despite the fact that many
study results show that the green roofs are the best management practices because of multiple social, environmental and
economic benefits, but many factors which includes (high initial cost, unawareness the green roofs construction
mechanics and maintenance costs and so forth.) still hinder the green roofs in underdeveloped nations. An ideal green roof
design that can apply to the all places and weather circumstance is also one of the biggest challenges. As most of the
researches have been carried out in cold areas, therefore the selection of the green roof plant needs extra attention. On the
contrary, in hot regions, there's a need to pick the right plant for the higher overall performance of green roof within the
summer season. These research challenges and issues associated with green roof research, we think, are connected to each
other and need to be researched further for the successful implementation of green roofs everywhere.
Also, it is important to consider multiple factors like initial high construction cost, reduction of use of polymer material
and their disposal, high maintenance costs, limited local research, roof leakage problems, and lack of cooperation between
different fields that hinder us from solving challenges that will benefit the use of green roofs in an urban context.
The main technical difficulties regarding the application of green roofs, which are needed to be considered are listed
It is very hard to estimate the air quality, ecological improvement, temperature and noise reduction costs for life cycle
cost analysis of green roofs, so it is needed to carry out more studies with regards to the life cycle cost analysis that
includes the benefits listed above.
More effort is needed in order to find a better local substrate for the green roof, which can reduce the water quality
problems that green roofs struggle with.
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Air, water quality and thermal performance of green roofs should be advertised to attract stakeholders for the
application of green roofs.
Polymer materials that are used in green roof components should eliminate and find the Eco friendly that can enhance
the environment.
A huger effort is needed for the co-operation and collaboration between different fields for the application and
management of green roofs.
Research work on green roofs has been challenging and provides opportunities for researchers to focus on future research.
This paper, reviews literature regarding green roof properties, environmental, social and monetary benefits, challenges,
opportunities, and potential applications of green roofs. Although significant features have been reported, there are many
challenges such as high construction costs and management problems that should also be considered for the potential
applications around the world. In this paper, an effort was made to demonstrate how green roofing can help mimic the
natural hydrology as well as help prevent global warming which has become a major issue in both our political and
natural surroundings. There is also need to develop cost effective green roof practices for the many benefits
(environmental, social etc.) of green roof. Nonetheless, in order to make more progress. a more in-depth real experimental
work on each component of the green roof is required, and multidisciplinary research collaboration in dealing the
challenges is gravely needed.
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ResearchGate has not been able to resolve any citations for this publication.
Green roof is a passive cooling technique that stops incoming solar radiation from reaching the building structure below. Many studies have been conducted over the past 10 years to consider the potential building energy benefits of green roofs and have shown that they can offer benefits in energy reduction for winter heating as well as summer cooling. Green roofs have many benefits over conventional roofs: they reduce storm water run-off, the heat island effect in cities and energy requirements for cooling; all of this while sequestering some CO2 from the atmosphere. But because of their expense, the building industry has yet to fully embrace their large-scale implementation. Over the summer', two test structures, one with a green roof and the other with an RCC roof, were built and tested at the Ujjain Engineering College, Ujjain, RGPV University, to determine their cooling potential. Results indicate that the test cell with the green roof consistently performs better than those with the conventional cement RCC roof.
Green roofs have been proposed for sustainable buildings in many countries with different climatic conditions. A state-of-the-art review of green roofs emphasizing current implementations, technologies, and benefits is presented in this paper. Technical and construction aspects of green roofs are used to classify different systems. Environmental benefits are then discussed mainly by examining measured performances. By reviewing the benefits related to the reduction of building energy consumption, mitigation of urban heat island effect, improvement of air pollution, water management, increase of sound insulation, and ecological preservation, this paper shows how green roofs may contribute to more sustainable buildings and cities. However, an efficient integration of green roofs needs to take into account both the specific climatic conditions and the characteristics of the buildings. Economic considerations related to the life-cycle cost of green roofs are presented together with policies promoting green roofs worldwide. Findings indicate the undeniable environmental benefits of green roofs and their economic feasibility. Likewise, new policies for promoting green roofs show the necessity for incentivizing programs. Future research lines are recommended and the necessity of cross-disciplinary studies is stressed.
The large windows on the south-oriented façade of a passive house strongly contribute to building space heating. These windows constitute the passive solar heating system. This paper studies the active heating system of a passive house, which includes the following sub-systems: (1) solar thermal collectors, (2) a water storage tank, (3) a secondary water circuit, (4) a domestic hot water preparation system and (5) an air ventilation and heating system. Models for all sub-systems are presented. The integrated model was implemented to Pirmasens Passive House (Rhineland Palatinate, Germany). The active solar heating system provides a smaller amount of heat than the heat provided by the passive solar heating system. Almost all the solar energy collected is not used for space heating but to domestic hot water (DHW) preparation. However, there is still a need for the classical water heater to operate all over the year. Almost all space heating thermal load is covered by using the classical air heater that operates mainly during the nights from November to April. The solar fraction lies between 0.180 in February and 0.679 in October, with a yearly average of 0.446. The study reveals that on a yearly basis it is more advantageous to use vertical south-oriented solar collectors instead of roof placed collectors.
This study investigated the weather effect on thermal performance of a retrofitted extensive green roof on a railway station in humid-subtropical Hong Kong. Absolute and relative (reduction magnitude) ambient and surface temperatures recorded for two years were compared amongst antecedent bare roof, green roof, and control bare roof. The impacts of solar radiation, relative humidity, soil moisture and wind speed were explored. The holistic green-roof effect reduced daily maximum tile surface temperature by 5.2°C and air temperature at 10cm height by 0.7°C, with no significant effect at 160cm. Green-roof passive cooling was enhanced by high solar radiation and low relative humidity typical of sunny summer days. High soil moisture supplemented by irrigation lowered air and vegetation surface temperature, and dampened diurnal temperature fluctuations. High wind speed increased evapotranspiration cooling of green roof, but concurrently cooled bare roof. Heat flux through green roof was also weather-dependent, with less heat gain and more heat loss on sunny days, but notable decline in both attributes on cloudy days. On rainy days, green roof assumed the energy conservation role with slight increase instead of reduction in cooling load. Daily cooling load was 0.9kWhm−2 and 0.57kWhm−2, respectively for sunny and cloudy summer days, with negligible effect on rainy days. The 484m2 green roof brought potential air-conditioning energy saving of 2.80×104kWh each summer, equivalent to electricity tariff saving of HK$2.56×104 and upstream avoidance of CO2 emission of 27.02t at the power plant. The long-term environmental and energy benefits could justify the cost of green roof installation on public buildings.
This paper presents field monitoring results from a 235 m(2) extensive living roof in Auckland New Zealand (NZ) The extent of stormwater control is quantified by comparing three different substrate types (Pumice Zeolite and Expanded Clay all pumice based but named for their distinguishing components) at two different substrate depths (50 and 70 mm) in a side-by-side comparison No statistically significant differences in runoff response were found between the three substrate types tested or the two different depths The cumulative retention efficiency of the living roof was 66% based on 12 months of continuous monitoring On an event basis the living roof demonstrated reductions in both volume and peak flow rates regardless of the rainfall and climatic characteristics The living roof retained a median of 82% of rainfall received per rainfall event with a median peak flow reduction of 93% compared to rainfall intensity The hydrologic response of a living roof is controlled by multiple parameters such as rain depth rain intensity climatic variables and antecedent dry days Detailed analysis indicates that antecedent dry days have the greatest influence on retention Seasonal differences do not influence runoff response living roofs will effectively moderate runoff hydrology year round in Auckland s sub-tropical climate (C) 2010 Elsevier B V All rights reserved
Two studies were conducted on a third-story rooftop to quantify the effect of solar radiation (full sun versus full shade) on several US native and non-native species for potential use on extensive green roofs. In the first study, plugs of six native and three non-native species were planted in May 2005 on substrates of two different depths (8.0 and 12.0 cm) both in sun and shade. Absolute cover (AC) was recorded using a point-frame transect during the growing season beginning in June 2005 and every 2 weeks thereafter for a period of 4 years. By week 174 (23 September 2008), most species exhibited different AC within a depth between sun and shade. However, when all species were combined, overall AC did not differ between sun and shade within a depth. This indicated that while species make-up was changing among solar radiation levels, that overall coverage was not significantly different between sun and shade. For all substrate depths and solar levels, the most abundant species were Sedum acre, Allium cernuum, Sedum album ‘Coral Carpet’, and Talinum calycinum. Less abundant species included Talinum parviflorum, Carex flacca, Sedum stenopetalum, and Sedum divergens, which all exhibited 0 or near 0 AC regardless of depth or solar radiation levels. With the exception of T. calycinum, native species were less abundant than non-native species.
The contribution of green roofs to urban water quality, either as sinks or sources of pollutants, is an open question. This study examined leaching of Cd, Fe, Ni, Pb, and Zn from simulated green roof systems that had been deployed under field conditions and naturally leached for 22 months. The objectives were to determine if Arkalyte (an expanded clay), when mixed with pine bark as a substrate, leached metals and if so, whether leaching was influenced by the depth of substrate, structural components of the green roof system, or wet/dry deposition. Leachate was collected from each system after wet deposition events in June 2007, October 2007, February 2008, and April 2008 and analyzed. The concentration of four elements routinely exceeded USEPA water quality criteria for chronic and/or acute toxicity and were therefore of possible relevance to water quality, particularly for Pb. The frequency and intensity of local wet deposition influenced the volume of leachate recovered from the systems and in some instances the corresponding metal concentration in the leachate. There were no consistent trends with respect to depth and metal concentration in the leachate, due perhaps to the confounding effects caused by leaching of metals from materials used to construct the built-in-place systems and from inputs from deposition. Further evaluation of this substrate and the structural materials is needed to determine if their use in green roof systems will improve or degrade urban water quality.
Cool roofs, cool pavements, and urban vegetation reduce cooling energy use in buildings, lower local air pollution, and decrease greenhouse gas (GHG) emissions from urban areas. To promote widespread and large-scale implementation of cool roofs to moderate urban heat-island phenomenon, more awareness and understanding of cool roof benefits at the local level is needed. As part of an investigation of strategies to mitigate urban heat-island effects, field data gathered from a monitoring project on cool roofs in India were reviewed. An innovative field-based analytical method was developed to quantify cooling energy savings resulting from the installation of cool roofs on commercial buildings. For buildings monitored in the Metropolitan Hyderabad region, the measured annual energy savings from roof-whitening of previously black roofs ranged from 20 to 22 kWh/m2 of roof area, corresponding to a cooling energy use reduction of 14–26%. The application of white coatings to uncoated concrete roofs resulted in annual savings of 13–14 kWh/m2 of roof area, corresponding to cooling energy savings of 10–19%. The annual direct CO2 reductions associated with the reduced cooling energy use were estimated to be 11–12 kg CO2/m2 of flat roof area. Additional field work on various building types and locations will help to understand magnitudes of regional or global potential in energy savings and GHG emission reductions from applying cool roofs. Knowledge about quantified cool roof benefits at both the local and regional level may promote the formulation of new policies and programs throughout the world.
Performance of vegetated roofs are investigated in terms of their expected benefits for the building and the urban environment, due to their recognised energy and water management potential scores. A review of related worldwide experiences is reported for comparison purposes. The investigation is here performed within the specific climatic context of the Mediterranean region. Full-scale experimental results are provided from two case studies, located in north-west and central Italy, consisting in two fully monitored green roofs on top of public buildings. The attenuation of solar radiation through the vegetation layer is evaluated as well as the thermal insulation performance of the green roof structure. The daily heat flow through the roof surface is quantified showing that the green roof outperforms the reference roof, therefore reducing the daily energy demand. As for water management, it is confirmed that green roofs significantly mitigate storm water runoff generation – even in a Mediterranean climate – in terms of runoff volume reduction, peak attenuation and increase of concentration time, although reduced performance could be observed during high precipitation periods.