scholarly journals GREEN ROOFS TO IMPROVE THE ENERGY RENOVATION RESILIENCE OF HISTORIC BUILDINGS

Author(s):  
Giovanni Santi ◽  
Sara Battini

The introduction of vegetation in urban areas, through both green roofs and green walls, is a sustainable strategy for improving the environment and the quality of life, as well as crucial for urban biodiversity since the moment it is able to create new habitats for plant and animal species. The design and realization of green roof systems abroad is promoted and stimulated while in Italy, this subject, is still an innovation not supported by many real implementations. The application of this technological green system has a great importance for the redevelopment of existing building heritage, especially for historic buildings, to improve their energy-performance qualities, with respect for their architectural value. The aim of this study is to identify the technical issues for the realization of green roofs in urbanized contexts by focusing on the implementation of a green roof on a building of Leghorn following intervention guidelines developed. This research shows that not only does this system allow higher energy saving, but it also brings a decrease of load bearing on the structure.

2018 ◽  
Vol 13 (2) ◽  
pp. 42-54 ◽  
Author(s):  
Jarrett Okita ◽  
Cara Poor ◽  
Jessica M. Kleiss ◽  
Ted Eckmann

Green roofs have become a common method to increase water retention on-site in urban areas. However, the long-term water quality of runoff from green roofs is poorly understood. This study evaluated the water quality of stormwater runoff from a regular (non-vegetated) roof, a green roof installed 6 months previously, and a green roof installed 6 years ago in Portland, Oregon. Samples of runoff were taken during every rain event for 10 months, and analyzed for total phosphorus (TP), phosphate (PO3-4), total nitrogen (TN), nitrate (NO-3), ammonia (NH3), copper (Cu), and zinc (Zn). Runoff from the green roofs had higher concentrations of TP and PO3-4 and lower concentrations of Zn compared to the regular roof. Average TP concentrations from the 6-year old roof and 6-month old roof were 6.3 and 14.6 times higher, respectively, than concentrations from the regular roof, and average PO3-4 concentrations from the 6-year old roof and 6-month old roof were 13.5 and 26.6 times higher, respectively, compared to the regular roof. Runoff from the 6-month old green roof had higher concentrations of TP and PO3-4 than the 6-year old green roof during the wet season, but lower concentrations during the dry season. The 6-month old green roof installations where receiving waters are sensitive or impaired may need additional treatment methods to reduce phosphorus levels. As green roofs age, water retention decreases and phosphorus leaching increases during the dry season.


2021 ◽  
Vol 13 (4) ◽  
pp. 1972
Author(s):  
Jeremy Wright ◽  
Jeremy Lytle ◽  
Devon Santillo ◽  
Luzalen Marcos ◽  
Kristiina Valter Mai

Urban densification and climate change are creating a multitude of issues for cities around the globe. Contributing factors include increased impervious surfaces that result in poor stormwater management, rising urban temperatures, poor air quality, and a lack of available green space. In the context of volatile weather, there are growing concerns regarding the effects of increased intense rainfalls and how they affect highly populated areas. Green roofs are becoming a stormwater management tool, occupying a growing area of urban roof space in many developed cities. In addition to the water-centric approach to the implementation of green roofs, these systems offer a multitude of benefits across the urban water–energy–food nexus. This paper provides insight to green roof systems available that can be utilized as tools to mitigate the effects of climate change in urbanized areas. A new array of green roof testing modules is presented along with research methods employed to address current issues related to food, energy and water performance optimization. Rainwater runoff after three rain events was observed to be reduced commensurate with the presence of a blue roof retention membrane in the testbed, the growing media depth and type, as well as the productive nature of the plants in the testbed. Preliminary observations indicate that more productive green roof systems may have increasingly positive benefits across the water–energy–food nexus in dense urban areas that are vulnerable to climate disruption.


Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1253 ◽  
Author(s):  
Dirk Cirkel ◽  
Bernard Voortman ◽  
Thijs van Veen ◽  
Ruud Bartholomeus

Worldwide cities are facing increasing temperatures due to climate change and increasing urban density. Green roofs are promoted as a climate adaptation measure to lower air temperatures and improve comfort in urban areas, especially during intensive dry and warm spells. However, there is much debate on the effectiveness of this measure, because of a lack of fundamental knowledge about evaporation from different green roof systems. In this study, we investigate the water and energy balance of different roof types on a rooftop in Amsterdam, the Netherlands. Based on lysimeter measurements and modeling, we compared the water and energy balance of a conventional green roof with blue-green roofs equipped with a novel storage and capillary irrigation system. The roofs were covered either with Sedum or by grasses and herbs. Our measurements and modeling showed that conventional green roof systems (i.e., a Sedum cover and a few centimeters of substrate) have a low evaporation rate and due to a rapid decline in available moisture, a minor cooling effect. Roofs equipped with a storage and capillary irrigation system showed a remarkably large evaporation rate for Sedum species behaving as C3 plants during hot, dry periods. Covered with grasses and herbs, the evaporation rate was even larger. Precipitation storage and capillary irrigation strongly reduced the number of days with dry-out events. Implementing these systems therefore could lead to better cooling efficiencies in cities.


2018 ◽  
Vol 10 (11) ◽  
pp. 4209 ◽  
Author(s):  
Ibrahim Salman ◽  
Leon Blaustein

Worldwide, urban areas are expanding both in size and number, which results in a decline in habitats suitable for urban flora and fauna. The construction of urban green features, such as green roofs, may provide suitable habitat patches for many species in urban areas. On green roofs, two approaches have been used to select plants—i.e., matching similar habitat to green roofs (habitat template approach) or identifying plants with suitable traits (plant trait approach). While both approaches may result in suitable habitats for arthropods, how arthropods respond to different combinations of plants is an open question. The aim of this study was to investigate how the structural complexity of different plant forms can affect the abundance and richness of arthropods on green roofs. The experimental design crossed the presence and absence of annuals with three Sedum sediforme (Jacq.) Pau (common name: stonecrops) treatments—i.e., uniformly disrupted Sedum, clumped disrupted Sedum, and no Sedum. We hypothesized that an increased structural diversity due to the coexistence of different life forms of plants on roofs is positively related to the abundance and richness of arthropods. We found that arthropod abundance and richness were positively associated with the percent of vegetation cover and negatively associated with substrate temperature. Neither arthropod abundance nor richness was influenced by the relative moisture of substrate. We also found that arthropod abundance and richness varied by green roof setups (treatments) and by seasonality. Arthropod abundance on green roofs was the highest in treatments with annuals only, while species richness was slightly similar between treatments containing annuals but varied between sampling periods. This study suggests that adding annuals to traditional Sedum roofs has positive effects on arthropods. This finding can support the development of biodiverse cities because most extensive green roofs are inaccessible to the public and can provide undisturbed habitat for several plant and arthropod species.


Author(s):  
Ar. Ankur Bhardwaj ◽  
Dr. Shweta Chaudhary ◽  
Ar.Kirti Varandani

The ecological, social and visual commitments that green roofs can make towards sustainable living in more intensified urban centres are generally recognized around the world. Green roof is one such sustainable methodology, utilization of which causes us in insulating the buildings and, subsequently contributing to better energy proficient execution of the same. Green roofs additionally give environment to various species, lessen the rainwater runoff and better deal with the carbon-dioxide cycle. In spite of these advantages, Green roofs are not as basic an element in India as they are in other European and American urban areas. In this paper an attempt has been made to enhance the advantages of this innovation in India. Green roofs systems looks simple in terms of setting up, but actually very complex in maintaining and achieving sustainability. In depth study of green roofs, historic background, climatic zones, impacts of green roofs on heating and cooling, benefits, problems and opportunities is done with the help of data taken from secondary sources like books, magazines and published literature (articles, journals, conference proceedings) form various e-libraries and other online platforms. KEY WORDS: Heating, Cooling, Green Roof, Sustainability)


2020 ◽  
Vol 21 (2) ◽  
pp. 99-104
Author(s):  
Mariam Bozhilova ◽  
Miglena Zhiyanski ◽  
Plamen Glogov

There are 265 municipalities in Bulgaria. According to the national legislation, each Municipal Coun-cil adopts an Ordinance for the construction and protection of the green system. Most of the mu-nicipalities have such ordinances, however, only 75 of them stipulate regulative requirements, under which a green roof can be considered a green area. These requirements refer to the substrate depth and are unreasonably high. While positive impacts are reported in green roofs with a substrate layer thickness of 4 – 5 cm, green roofs with substrate depth under 10 cm are not considered a green area in any of the reviewed ordinances. One municipality considers green roofs with substrate 10-30 cm as a green area, under specific conditions. This paper provides a review of the stipulations of the Bulgarian local legislation against the existing data for the effects of green roofs with different substrate depths and outlines the need for amendment of the legislation and future research. 


2019 ◽  
Vol 28 (4) ◽  
pp. 632-640
Author(s):  
Anna Baryła ◽  
Agnieszka Bus ◽  
Agnieszka Karczmarczyk ◽  
Joanna Witkowska-Dobrev

Increasing urban populations raises a number of problems and risks that are strengthened by observed and projected climate change. An increase in green areas (so-called green infrastructure) has turned out to be an effective means of lowering temperature in the city. Green roofs can be one of the possible measures leading to achieving this aim. The aim of the study was the analysis of temperature changes of different roof surfaces (conventional roof, board, intensive roof substrate without plant cover, substrate covered with plants (shrubs). Studies on comparing the temperature between a conventional roof and green roofs were carried out in the period from April to September 2015 on the roof of the building of the Faculty of Modern Languages, University of Warsaw. The measurement was performed using the FLIR SC620 thermal imaging system. As a result of the tests, it was found that in the summer months the differences between the temperature of the green roof and the conventional roof amounted to a maximum of 31.3°C. The obtained results showed that the roof with vegetation can signifi cantly contribute to the mitigation of the urban heat island phenomenon in urban areas during summer periods.


2019 ◽  
Vol 28 (4) ◽  
pp. 641-652 ◽  
Author(s):  
Ewa Burszta-Adamiak ◽  
Wiesław Fiałkiewicz

Nowadays green roofs play a key role in alleviating the negative effects of urbanization. Despite investors awareness of the advantages of green roofs, there are still some barriers that hinder investments on a large scale. As a result a financial and non-financial incentives are implemented. The review presented in this paper allowed to identify the most popular initiatives and to formulate recommendations for creating incentive supporting implementation of green roofs in urban areas.


2021 ◽  
Vol 67 (3-4) ◽  
pp. 149-155
Author(s):  
Har'el Agra ◽  
Hadar Shalom ◽  
Omar Bawab ◽  
Gyongyver J. Kadas ◽  
Leon Blaustein

Abstract Green roofs are expected to contribute to higher biodiversity in urban surroundings. Typically, green roofs have been designed with low plant diversity. However, plant diversity can be enhanced by controlling resource availability and creating distinct niches. Here we hypothesize that by using different drainage heights during the short plant-growing season in a semi-arid green roof system we can create distinct niches and plant communities. Our experiment took place at the University of Haifa, north Israel. We tested three different heights of drainage outlet: 10 cm under the surface of the substrate (Low), 1 cm under the surface of the substrate (Medium) and 3 cm above the surface of the substrate (High) on plant species-composition in green-roof gardens. Grasses cover was higher in High and Medium drainages while forbs cover was higher in Low drainage. Species richness was the highest in Low drainage while diversity indices showed the opposite trend. We conclude that by changing the height of the drainage we can create different niches and change species composition in a short time period of one growing season. This way we can create more diverse green roof communities and enhance biodiversity in urban areas, particularly in semi-arid regions.


Author(s):  
Darija Gajić ◽  
Erdin Salihović ◽  
Nermina Zagora

Yielding from an overall quantitative study of the residential sector of Bosnia and Herzegovina (B&H), this chapter concentrates on the ratio between single-family and collective housing, as well as on the urban-rural ratio of the single-family housing. Based on the data from the existing building stock (buildings built by 2014) and the statistical estimates, 23% of the buildings belong to the urban areas and 77% belong to the rural areas. The main goal was to study the correlation between the characteristics of the building envelope, the shape factor (A/V ratio) and the energy savings potential for the application of conventional measures of refurbishment of the building envelope of the single-family houses (type of buildings, which dominate in rural and urban areas). The chapter wraps up with recommendations for the adequate level of the energy performance indicator (energy need for heating) for the approved energy class for single-family houses located in the climate zone of the northern B&H.


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