Search Results (1,537)

Between 51% and 72% of a bituminous roofing membrane used for structural waterproofing consists of organic material, predominantly bitumen—a derivative of crude oil refining—highlighting the strong dependence of this product on fossil resources. Considering that several tonnes of these membranes must be replaced every 30 to 50 years, substantial potential exists for emission reduction through the establishment of circular material systems. This study investigates this potential by analysing 26 Environmental Product Declarations (EPDs) and life cycle datasets from across Europe covering the period from 2007 to 2023. To ensure comparability, all data were normalised to a declared unit of 1 kg of roofing membrane. The reinforcement layers were categorised into glass and polyester & glass composites, and their differences were examined using Welch’s t-tests. Correlative analyses and linear as well as multiple regression models were then applied to explore relationships between environmental indicators and the shares of organic and mineral mass fractions. The findings reveal that renewable energy sources, although currently representing only a small share of total production energy, provide a major lever for reducing nearly all environmental impact categories. The type of reinforcement layer was also found to influence the demand for fossil resources, both materially and energetically. For most environmental indicators, only multiple regression models can explain at least 30% of the variance based on the proportions of organic and mineral inputs. Overall, the study underscores the crucial importance of high-quality, transparently documented product data for accurately assessing the sustainability of building products. It further demonstrates that substituting fossil energy carriers with renewable sources and optimising material efficiency can substantially reduce environmental burdens, provided that methodological consistency and clarity of indicator definitions are maintained. Full article

This study investigates the adoption and utilisation of hidden roof construction as an innovative alternative to traditional roofing systems in Ghana’s urban housing. Although hidden roofs offer advantages in climate adaptability, aesthetics, and cost efficiency, their adoption remains limited. Using a survey-based partial least squares structural equation modelling approach, this study identifies the factors influencing their acceptance and use. Quantitative data were collected through field surveys from residents and construction professionals within the Kumasi Metropolitan Area. A structured questionnaire was administered using purposive and convenience sampling, yielding 175 valid responses from a total of 220 distributed questionnaires (79.5% response rate). Findings indicate that hidden roof systems are valued for their climatic suitability, particularly their resistance to water leakage and reduced heat absorption, alongside their efficient drainage design. Aesthetic appeal, cultural relevance, and ease of maintenance also emerged as key determinants of positive perception and adoption. Structural analysis confirmed significant positive relationships between design concept, aesthetic and social values, sustainability, functionality, and overall acceptance. The study provides practical guidance for architects, engineers, developers, and policymakers seeking to promote sustainable, user-centred roof design in tropical urban contexts. Findings are, however, limited to Kumasi and may not fully generalise to other Ghanaian cities. Full article

Within the scope of this article is the presentation of a modelling and measurement approach for the effects of roof greenings and the application of the approach to evaluate the influence of roof greenings upon the thermal conditions inside a typical residential building. It is shown that overheating in summer can be reduced, and thermal comfort for inhabitants can be increased. The cooling is caused by the transpiration of plants and by the evaporation of water from the substrate. Other relevant physical effects are the shading of plants and the increase in the heat capacity of the building. In state-of-the-art buildings, a layer with a high insulating effect is incorporated into the envelope. This leads to the effect that a huge fraction of the cooling power is taken from the outside of the building and only a smaller part is taken from the inside. In order to mitigate this decoupling, a hydraulic connection between the greening and the interior of the building is introduced. To evaluate the effect of the inside cooling, the difference in the number of yearly hours with overheating in residential buildings is estimated. In addition, the reduction in energy demand for the climatisation of a typical residential building is calculated. The used methods are as follows: (1) Performance of laboratory and free field measurements. (2) Simulation of a typical residential building, using a validated approach. In summary, it can be said that green roofs, in particular with hydraulic connections, can significantly increase the interior thermal comfort and potentially reduce the energy required for air conditioning. Full article

Deep soft rock roadways at about 1 km depth experience significant deformation due to concentrated stress ahead of the working face and dynamic loads from the hard roof layer. We propose an integrated control method that couples directional roof cutting, which interrupts stress transfer with constant resistance, and large deformation cable reinforcement to accommodate residual movement. The calibrated FLAC3D model indicates a lower front of face stress and a diminished cyclic build up of elastic strain energy in the roof, which reduces roadway convergence. Field data from Face 13403 corroborate the method’s effectiveness: the average hydraulic support load on the roof cutting side was 20.3 MPa, which is 30.1% lower than on the non-cutting side; deformation stabilized about 320 m behind the face; the final roof to floor and rib to rib closures were 1.10 m and 1.47 m; and the entry remained fit for the next panel. These results indicate that coupling roof cutting with constant resistance cable reinforcement reduces mining-induced loads while increasing deformation tolerance, providing a practical solution for stabilizing kilometer-deep soft rock roadways. Full article

Reusing existing buildings is a valid response to the architectural challenge associated with addressing climate change and can aid the regeneration of the historic built environment. This demands sensitive architectural conservation strategies that improve thermal comfort, indoor environmental quality, and energy efficiency. In addition, energy retrofit solutions that balance performance improvements with the conservation of cultural and architectural values are needed to achieve higher performance while preserving cultural heritage, architectural features, and identity. Energy retrofits of post-war, mid-20th-century buildings pose particular challenges, including low ceiling heights, full-height windows, external decorative components, and other structural aspects, as these features hinder thermal upgrades. Concrete buildings from this period are frequently demolished due to limited guidance on effective retrofit methods. This study explores the most effective energy retrofit strategies for balancing energy efficiency with conservation requirements in such buildings, and assesses the risks associated with condensation and thermal bridging arising from internal insulation strategies. This paper examines internal insulation as a retrofit solution, where external insulation is not feasible. Internal wall insulation (IWI) reduces overall heat loss but concentrates thermal transfer at uninsulated junctions, thereby increasing the risk of condensation. In the simulated case, a relatively thin, short strip of slab insulation, combined with wall insulation, significantly reduced condensation and mould risk, suggesting a potential solution for mid-century building types. The analysis shows that applying insulation asymmetrically worsens conditions on the uninsulated side. Full-height window replacement, coupled with internal slab insulation, results in the most significant improvement; however, slab insulation alone can mitigate condensation risks where window replacement is not permitted. Findings highlight that partial insulation at balconies, parapets, and roof junctions is minimally effective, reinforcing the importance of integrated internal strategies for successful retrofits. Full article

This study evaluates integrated water-saving strategies in two school centres (SC1 and SC2) located in Bragança, Portugal, combining rainwater harvesting systems (RWHS), green roofs (GR), and the replacement of conventional taps with high-efficiency models. Water consumption patterns were analysed, and nine scenarios were simulated to assess their feasibility and economic performance. Scenario 1, which focuses on replacing conventional taps, achieved the highest short-term cost-effectiveness, reducing potable water consumption by approximately 30% and providing a payback period of about one year. Scenario 3, integrating RWHS into conventional roofs with efficient taps, demonstrated the greatest overall benefits, reducing potable water demand by up to 60% and generating annual savings exceeding €7000 + VAT, with payback periods of eight years for SC1 and seven years for SC2. In contrast, scenarios involving extensive GR significantly reduced stormwater runoff but required higher investments and presented longer payback periods, ranging from 17 to 42 years. Overall, the results indicate that combining low-cost efficiency measures with RWHS maximises potable water savings and supports sustainable water management, while GR implementation should be considered selectively, particularly when broader ecological and thermal benefits are prioritised. Full article

The identification of strategies to mitigate climate change and address urban challenges is nowadays a priority for urban planners. The installation of green roofs (GR), as a natural-based solution, is widely promoted. Despite this recognition, most installations result from individual initiatives, and their mapping and monitoring remains absent. Over time, the installation of green roofs has followed the building construction sector, moving from individual to groups of buildings organ, grouped in condominiums, on which common shared areas at ground level are covered with GR. The identification of those GRs is important, as they represent the majority of the GR installations in urban areas; however, this task is still very challenging due to the lack of information about the condominium boundaries. This work proposes a methodology for mapping GR at a top and ground level, and monitoring them, through the use of Support Vector Machine classification process, deep learning models, and GIS-based spatial analysis. Applied to the Lisbon Municipality, the methodology enabled the identification and validation of 196 GR. The results demonstrate the effectiveness and scalability of the proposed approach, which surpasses existing methods and is adaptable to diverse urban contexts without reliance on location-specific characteristics. Full article

The standing seam metal roof system is wind-sensitive due to its light weight and decreasing stiffness as the span increases, and in recent years there have been a number of wind-exposed damages to the structures where these roof systems have been applied. In order to study the wind-uplifted resistance reliability of different types of standing seam metal roof systems, and then to evaluate their safety level, a reliability analysis framework was developed. The proposed approach integrates the Latin Hypercube Sampling–Monte Carlo Simulation (LHS–MCS) method to assess the wind-uplifted resistance reliability of standing seam metal roof systems. Taking Jinan Yaoqiang International Airport Terminal Building’s standing seam Al-Mg-Mn roof system and Urumqi Tianshan International Airport Transportation Center’s standing seam Al-Zn-plated steel roof system as the objects of research, the research was carried out from the aspects of wind uplift test, wind tunnel test, finite element simulation, and wind-uplifted resistance reliability analysis. The study shows the following: the wind-uplifted resistance bearing capacity of the roof systems is significantly affected by the width of the roof panel, the spacing of the fixed support, the thickness of the roof panel, and the diameter of end interlocking; the effects of the differences in structural parameters and roof types are eliminated by the introduction of a damage index, and the failure forms of different types of roof systems can be unified, and the corresponding limit state function can then be deduced; based on the LHS–MCS method, the reliability indexes of the two common types of standing seam metal roof systems were obtained to be 3.0975 and 3.2850, respectively, which are lower than the requirements of the code for the first safety level, and it is recommended that reinforcement measures be prioritized at the connection points between roof panel and support, such as reducing the spacing of the fixed support or decreasing the diameter of end interlocking, to improve the structural safety. The above study can provide a reference for the safety level assessment, wind resistant design, and sustainable operation and maintenance of different types of standing seam metal roof systems. Full article

Building-Integrated Photovoltaics (BIPV), which are used for building exteriors such as walls, roofs, balconies, and awnings, play a significant role in reducing greenhouse gas emissions. However, since the back sheet, sealant, junction box, and cable of BIPV modules are made of flammable plastic materials, fire protection technologies are needed to ensure fire safety. The aim of this work is to evaluate the fire safety performance of BIPV modules coated with fire-resistant (FRs) and flame-retardant (FRt) materials. The test results show that the performance of the FRs coating was excellent in terms of fire blocking, physical properties, and durability, compared to the FRt coating. Surface damage, such as cracks and blisters, was observed on the FRt coating during the impact and acid resistance tests, whereas the FRs coating demonstrated superior durability without any defects. Specifically, aluminum hydroxide (ATH, 5–10 wt%) added to the FRs coating promoted an endothermic reaction that lowered the flame temperature, released H₂O, and stably formed an Al₂O₃ heat-shielding layer. Due to this reaction, the suppression of the fire spread by the BIPV modules was the best compared to that of Mg, Ti, and Si-based additives. Full article

Integrating renewable energy into heritage buildings poses technical, aesthetic, and regulatory challenges, especially in Andean cities with a rich historical legacy, such as Cuenca, Ecuador. This study addresses the design and implementation of a prototype for handcrafted photovoltaic roof tiles that comply with the conservation regulations of the Historic Center. The proposed solution is sustainable, visually unobtrusive, and suitable for heritage urban environments. A technical assessment was conducted for 23 educational institutions located in the Historic Center to evaluate the structural suitability of their roofs for solar panel installation. Based on this assessment, a photovoltaic roof tile prototype was developed using accessible materials, such as terracotta-tinted acrylic, and evaluated in terms of energy efficiency, architectural integration, and regulatory compliance. As a result, 12 buildings were found to be structurally suitable for system installation, of which 11 had sufficient roof space to meet their daytime energy demands. The prototype proved to be functional, replicable, aesthetically harmonious with the heritage setting, and fully compliant with current municipal regulations. The School of Law at the Catholic University of Cuenca was selected as a demonstration site due to its technical suitability and heritage significance. Thus, handcrafted photovoltaic roof tiles emerge as an innovative and viable solution for incorporating solar energy into protected urban settings, offering environmental, technical, and social benefits. Lastly, this study outlines future research pathways aimed at developing new materials, advancing energy storage strategies, and exploring community perceptions in heritage environments. Full article

The intensification of thermal extremes increases the need for strategies that protect indoor comfort and reduce the energy demand of active systems. This study employs EnergyPlus dynamic simulations to evaluate how passive thermal design solutions for heating and cooling can minimize indoor temperature fluctuations. The analysis covers multiple locations to identify the most effective techniques for improving indoor thermal performance and energy efficiency. Results demonstrate that passive thermal strategies offer a sustainable and efficient approach to adapting buildings to extreme temperature variations, thereby reducing dependence on mechanical systems. The greatest reduction in energy demand is achieved by increasing the envelope’s thermal mass, particularly in hot and temperate climates. Enhanced insulation and green roofs are more effective in cold and humid climates. In addition, solar control measures, such as external shading and reduced glazing areas, help lower indoor temperatures in high-thermal-radiation regions. Full article

Free-form grid structures offer both aesthetic appeal and structural efficiency in long-span roof design and application, yet the potential of morphological design to optimize thermal performance has been long overlooked. This study proposes a multi-objective synergistic optimization framework which can improve the thermal environment and mechanical performance simultaneously for the roof. Focusing on public buildings in hot–humid climates, the research investigates the impact of roof geometry on indoor temperature under extreme thermal loading conditions and long-term thermal loading conditions. Furthermore, the evolution of thermal performance during mechanical performance-driven surface optimization is systematically analyzed. Subsequently, a dynamic proportional adjustment factor is introduced to explore the performance of the optimized results under different performance weights, with thermal and mechanical performance serving as the optimization objectives. Results demonstrate that thermal performance-driven optimization generates saddle-shaped free-form surfaces with alternating peak–valley configurations to achieve self-shadowing effects, reducing indoor temperature by approximately 2 °C but significantly compromising structural stiffness. Conversely, strain energy minimization yields moderate indoor temperature reductions, revealing a positive correlation between strain energy decrease and thermal performance improvement. In the multi-objective optimization considering thermal and mechanical properties, when the strain energy ratio is 0.5–0.7 (optimization balance zone), the indoor temperature decreases, while the structural stiffness and stability bearing capacity increase. This study provides a morphological–structural–environmental synergistic design reference for low-carbon long-span building roofs. Full article

Informal settlements, urban areas with substandard housing conditions and inadequate infrastructure, are increasing in Africa’s sub-Saharan cities, fueled by rapid urbanization, economic challenges, and high housing prices. However, developers often ignore the green building (GB) concept when upgrading housing conditions for these communities. This study aims to investigate GB design strategies specifically for residential structures in Akabahizi to identify and propose practical strategies suitable for informal settlements such as Akabahizi and to develop sustainable housing solutions that enhance environmental quality and meet the needs of residents. Simulation software and combined qualitative and quantitative data collection techniques, including field surveys, interviews, and assessments of existing building conditions, constitute the methodology used in this study. The focus was on the influence of climatic factors, including temperature, precipitation, and wind, on design choices, particularly GB design and current residential buildings in Akabahizi. Based on the survey, 82.5% of residents support the GB concept, 87.4% recognize the importance of GB for community well-being, and 97.1% recognize the benefits of integrating energy-efficient technology for residents’ well-being. Questionnaire findings were considered in decision-making for the design of the new proposed structure to address challenges in the area. Optimized energy efficiency, daylight access, and thermal comfort resulting from courtyard design support GB design incorporating a courtyard as a robust and culturally relevant sustainable design framework tailored for Akabahizi. The courtyard provides green space that promotes social interaction, improves air quality, and delivers natural cooling elements that are essential for residential housing. The proposed new design, with green roof and renewable energy devices, improved material usage, and natural ventilation elements, outperformed the existing one in terms of lower levels of carbon emission for environmental protection. In conclusion, a collaborative effort is needed among various stakeholders, including architects, urban planners, and educational institutions, to promote and implement sustainable building practices. The study suggests that enhancing awareness, offering training opportunities, and empowering local professionals and residents alike can pave the way for improved living conditions and sustainable urban development in Akabahizi and similar informal settlements. Full article

In the context of China’s rural revitalization strategy, improving the livability and sustainability of traditional dwellings in border regions has become a critical priority. This study examines Chinese–Korean houses in border villages, where field investigations and quantitative analysis reveal persistent challenges: poor indoor thermal comfort and high energy consumption due to outdated building envelopes and inefficient heating systems. To address these issues, we propose an integrated retrofitting solution that combines building-integrated photovoltaics (BIPV) and ground-source heat pump (GSHP) technologies. Unlike previous studies focusing on isolated applications, our approach emphasizes the synergistic integration of active energy generation and high-efficiency thermal regulation, while preserving the architectural and cultural identity of traditional dwellings. Pilot results demonstrate significant improvements in PMV (Predicted Mean Vote) and economic viability, and achieve a high level of esthetic and cultural compatibility. Modular BIPV integration provides on-site renewable electricity without altering roof forms, while GSHP ensures stable, efficient heating and cooling year-round. This solution offers a replicable, regionally adaptive model for low-carbon rural housing transformation. By aligning technological innovation with cultural preservation and socioeconomic feasibility, the study contributes to a new paradigm of rural development, supporting ecological sustainability, ethnic unity, and border stability. Full article

The rapid increase in global human activities and urban surface modifications has exacerbated the urban heat island effect, prompting growing scholarly efforts to adopt various measures for mitigating heat islands worldwide. This paper reviews existing literature on rooftop mitigation of UHI, summarizes specific existing rooftop mitigation measures, and examines the comparative effectiveness of various rooftop mitigation strategies in reducing urban heat islands. Findings indicate that cool roofs are the most effective rooftop measure for mitigating UHI, followed by green roofs and photovoltaic roofs. Simultaneously, the cooling effectiveness of rooftop mitigation strategies is influenced by their inherent characteristics (reflectivity, coverage, orientation, etc.), geographical and climatic features (latitude, humidity levels, temperature extremes, diurnal temperature variation, etc.), and urban morphology (building density, height, shape index, etc.). The research status summarized herein provides valuable insights for policy formulation and guides future studies, thereby promoting more innovative designs for sustainable urban roofs to mitigate UHI. Full article