Urban populations worldwide are expanding rapidly and consequently a large number of people are becoming exposed to hazards inherent in cites. Phenomena such as the urban heat island can exacerbate the effects of heatwaves, and land surface sealing can lead to flash flooding. Cities are also the sites of enhanced air and water pollution from non-point sources such as concentrated motor vehicle use. Climate change predictions for the UK include increased winter precipitation and an increase in frequency of summer heatwaves. This will put further pressure on urban residents and infrastructure. Roof greening can be used within climate change adaptation schemes because green roofs have a range of environmental benefits which can help urban infrastructure become more sustainable. This thesis empirically quantifies several of these benefits, and the processes influencing them, by monitoring real green roofs in Manchester. A number of novel discoveries were made. Green roofs act as passive filters of airborne particulate matter. 0.21 tonnes of PM10 (2.3% of the inputs) could be removed from Manchester city centre in a maximum extensive green roof scenario. Species and site differences in particle capture were exhibited and related to morphology and proximity to sources respectively. An intensive green roof was able to lower the monthly median overlying air temperature at 300 mm by up to 1.06 oC. A combination of drought and mismanagement caused damage to the vegetation on one of the green roofs, with a subsequent reduction in the cooling effect. Daytime air temperatures were higher than over an adjacent bare roof for a larger proportion of the day than over the undamaged roof, and lower cooling was observed at night. A site-specific methodology was devised to monitor the rainwater runoff from an intensive green roof and an adjacent bare roof. Average runoff retention of 65.7% was observed on the green roof, compared to 33.6% on the bare roof. Season and rainfall amount had significant impacts on retention, however, many other explanatory variables such as Antecedent Dry Weather Period (ADWP) and peak rainfall intensity had no demonstrable, significant impact. Intensive roof construction on 10% of the rooftops in Manchester city centre would increase annual rainfall retention by 2.3%. The runoff was characterised with regards to heavy metals and nutrients. Nutrient levels were found to be not a significant problem for water quality, however, Environmental Quality Standards (EQS) values for protection of freshwater were exceeded for concentrations of Cu, Pb and Zn. High metal concentrations within the sediments may be acting as sources of pollution, particularly in the case of Pb. The age of the green roof means that past atmospheric deposition of Pb could be contributing to the runoff quality. The multi-benefit aspect of green roofs is discussed in the light of the results of this thesis and recommendations made for policy makers and the green roof construction industry.

From the futuristic Jewel at Changi Airport, the healing gardens at Khoo Teck Puat Hospital in Yishun to School of the Arts at Orchard Road, greenery has sprouted in buildings vertically and horizontally in Singapore, painting a growing green canopy for the dense, high rise city. This paper combines both analyses from first-hand site visits and case studies from external scholar studies to examine the performance of existing Green Building Infrastructures (BGIs) within Singapore’s unique urban context. The study reveals that the success of BGIs is highly dependent on the programming (i.e. thermal comfort design, accessibility, amenity facilities etc.), as well as the function and users of the existing building. Designs and planning that take those factors into consideration while being in line with the city’s general development goals, such as storm water management and pervasive greenery, are likely to bring out the most benefits in BGIs. To demonstrate, this paper also proposed several policy and planning recommendations that included several sets of rudimentary yet relevant parameters. Future research is encouraged to explore more complex combinations of considerations, their incorporation in design and policy making process, as well as a scientific and systematic method to evaluate BGI performance that includes both objective environmental impacts and subjective user experience that might be achieved through smart city developments.

Expected effects from climate change are increased precipitation and rising temperatures. This in combination with urban densification where green areas are replaced by hard surfaces contributes to a higher risk of floods and heat islands, since green areas provide ecosystem services which disposes local stormwater and has a cooling effect. The aim of this study was to investigate how green roofs and its ecosystem services can contribute to more sustainable cities. This study was conducted by literature data combined with interviews. The result of this study showed that the most important function of green roofs is stormwater management. The space in cities is limited and many functions e.g., infrastructure and buildings should fit in limited surface. The lack of space is a problem to ensure that there are sufficient green spaces that provides ecosystem services. This problem could decrease by using the roofs to a greater extent to ensure ecosystem services in form of e.g., stormwater management. However, the municipalities’ room for maneuver to plan with green roofs showed to be limited by regulations. In conclusion, there is potential to build green roofs to a greater extent as they have many benefits that are useful in urban densification and to counteract negative effects of climate change, e.g., stormwater management and temperature control. The municipal actors would therefore need more room to maneuver to be able to implement green roofs in community planning to a greater extent.

The main objective of the research was to study the effect of the Stenotaphrum secundatum and Zoysia japonica grasses on the higher and lower environment temperature and lower relative humidity; the secondary objective was to compare whether the Stenotaphrum secundatum grass has a greater impact on the environment parameters of comfort than the Zoysia japonica species. Six materials were used for the extensive green roof, each one forming a layer of the system, which were placed on the concrete slab and in an upward direction, including: PVC geomembrane, Polyester asphalt carpet, Pumice stone, Planar geodren, Prepared soil with guano, compost, muss, and Substrate. In order to make measurements of the higher and lower ambient temperature, a digital thermometer and lower relative humidity meter was used. Stenotaphrum secundatum and Zoysia japonica were used as grass species, as they were the most representative of the grasses used in extensive green roofs. The experimentation was carried out for 2 months from September to October of 2021, having built 3 modules of 1000x600mm roofs, including 1module of the concrete roof with ceramic covering and 2 modules of extensive green roof with two types of grass: Stenotaphrum secundatum and Zoysia japonica. The readings of the environment temperature and relative humidity of the higher and lower part were taken in six points of each module to have a greater number of representative measurements. The watering of the 2 green roof modules with grass was carried out twice a week, applying 5L of water per module. The results indicate that the Zoysia japonica grass is the one that presents a better behavior before the higher ambient temperature and that the Stenotaphrum secundatum grass behaves better before the lower ambient temperature and lower relative humidity. The conclusions indicate that the Stenotaphrum secundatum grass behaves better temperature and relative humidity; the two grass types exhibit different behavior.

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Sustainable urban planning is becoming more and more important. Ecological sustainability holds greats opportunities for urban areas in order to avoid some of the consequences climate change might cause. In sustainable planning Grönytefaktorn (The Biotope Area Factor) is one important tool and one which Malmö Stad has used in order to increase sustainable planning in the city. Since the beginning of 2015, municipalities in Sweden are no longer required to use The Biotope Area Factor, which might threaten the development of e.g. green roofs. The aim of this study is to investigate how real estate companies experience their role as investors in sustainable planning. Planning is a political activity with multiple stakeholders and in order to try to understand the difficulties sustainable solutions face in this context, Planning theory and Theory of Planned Behavior have been used. The results show that the companies are not willing to invest in sustainable solutions like green roofs, unless the market demands it.

Green roofs can be an effective and appealing way to increase the energy efficiency of buildings by providing active insulation. As plants in the green roof transpire, there is a reduction in heat flux that is conducted through the green roof. The R-value, or thermal resistance, of a green roof is an effective measurement of thermal performance because it can be easily included in building energy calculations applicable to many different buildings and situations. The purpose of this study was to determine if an increase in ambient temperature would cause an increase in the R-value of green roofs. Test trays containing green roof materials were tested in a low speed wind tunnel equipped to determine the R-value of the trays. Three different plant species were tested in this study, ryegrass (Lolium perenne), sedum (Sedum hispanicum), and vinca (Vinca minor). For each test in this study the relative humidity was maintained at 45% and the soil was saturated with water. The trays were tested at four different ambient temperatures, ranging from room temperature to 120ºF. The resulting R-values for sedum ranged from 1.37 to 3.28 ft²h°F/BTU, for ryegrass the R-values ranged from 2.15 to 3.62 ft²h°F/BTU, and for vinca the R-values ranged from 3.15 to 5.19 ft²h°F/BTU. The average R-value for all the tests in this study was 3.20 ft²h°F/BTU. The results showed an increase in R-value with increasing temperature. Applying an ANOVA analysis to the data, the relationship between temperature and R-value for all three plant species was found to be statistically significant.

The building sector has for a longer period of time been responsible for a considerable part of the negative environmental imprint. The increased interest for the environment and sustainability in the industry has led to technological developments which has reduced the negative environmental impact from buildings. This, combined with the fact that buildings take up more space in cities reducing green spaces, has increased the use of green roofs. This research paper includes a study on the competitive advantages green roofs can offer property owners and what the driving forces behind the use of green roofs are. The study also includes a research on what benefits tenant’s experience from having offices in properties that have green roofs. Lastly, the study attempts to present why buildings should have green roofsand what motivates property owners to use them more often. The literature review reveals that green roofs have become popular due to their ability to absorb carbon dioxide, cool down cities, manage urban runoff and increase biodiversity. The literature review describes both the practical aspects of constructing a green roof and the management of green roofs. It also examines the cost of green roofs compared to conventional roofs. The main challenges with green roofs are said to be the increased risk of leakage, increased weight on roofs and the steep slopes of Swedish roofs. Green roofs are said to have a longer lifespan compared to regular roofs. The literature review also discusses market value and the parameters which affect the market value of a property. The research results demonstrate that it is difficult to link green roofs to an increased market value. Due to the regulation against particular, structural requirements the municipality cannot require property owners to implement green roofs. However, the municipality of Stockholm have requirements stating that each property owner is responsible for the management of urban runoff within the property lines. One way of solving this management is by using green roofs. The municipality may also require the GYF factor to be fulfilled during new construction, which means that a certain amount of green space is required. This is something green roofs can help property owners achieve as well. The LEED and BREEAM green building certification programs also require a certain amount of green spaces in order to generate a higher rating. Here, too, green roofs could be used for this aspect. The study also examines if LEED and BREEAM have any economic benefits. Interviews were conducted with property owners, tenants, architects and employees at the municipality of Stockholm. The results were relatively similar to that of the results of the literature review. Among the most important factors when considering building a green roof according to the property owners, were green certifications, the factor of green areas (GYF),stormwater management and biodiversity. The study revealed that the most important benefit for tenants was the ability of green roofs to help companies with their environmental profiling. The conclusion of the study is that the main driving factor for utilizing green roofs above all is that it helps the property owner to achieve a higher certification rating. For property owners this is important as they want to profile themselves in a sustainable and environmentally friendly way, which attracts tenants and investors. Certification programs are also leading to economic benefits for the property owners. Other driving forces for property owners to use green roofs are to meet the requirements of the municipality regarding urban runoff management and to reach the level of GYF required. As tenants often have strict sustainability policies, green roofs provide an added value as they are sustainable. In terms of cost, green roof is said to have initial costs of 300-600 kr/m2 which is higher than for conventional roofs. The short-term risk of leakage is refuted by this study, but the longtermrisk is still unknown. Even though higher initial cost and unknown long-term risk of leakage the study believes that implementing a green roof is justifiable; the positive environmental and social aspects outweighs the higher costs. Green roofs can provide a financial profit for the property owner when it’s combined with a green building certification;green roofs are a factor to implement in order to reach higher levels of green building certification systems LEED and BREEAM, which, in turn, can lead to a higher market value.The study also reveals that accessible green roofs can result in an increased revenue for the property owner.

Green roofs are an emerging technology promoted primarily for stormwater management but little has been published about their potential for biodiversity performance. This is the first study to explore the potential for creating prairie-like, non-succulent, native plant communities on unirrigated extensive green roofs in the southeastern United States. Ten experimental green roof platforms were used to: 1) identify native species and methods of establishment appropriate for green roof applications in the southeastern United States; 2) examine the effects of introducing natural soil into a commercially available green roof soil media mixture on the survival and establishment of native prairie species; and 3) examine the composition of early successional green roof plant communities. Eleven planted species were successfully established and 46 colonizing species were identified. It was found that the addition of native prairie soil did not significantly affect survival, overall cover, or biodiversity in terms of species richness and evenness.

Human settlement displaces and fragments natural habitats. Design choices in the landscape directly affect both local diversity and extinction rates. This study seeks to understand how avifauna are responding to this new technology in Mississippi.