Conventional Roof Research Articles

Evaluation of community-based heat adaptation interventions: a systematic review

Introduction Heat adaptation strategies are crucial to minimising the adverse effects of heat on human health. We systematically reviewed published studies till February 2024 to synthesise and evaluate the evidence of the impact of community-based heat adaptation strategies on surface and indoor temperatures and health outcomes. Methods Two investigators independently screened relevant databases and extracted data. The review included a total of 141 studies; 124 landscape interventions, out of which 114 focused on green walls/roofs and modified pavements, 21 building modifications including altered construction materials and improved ventilation; and 45 targeted individual-level interventions including heat education and warning systems, heat action plans and modifications in clothing. Meta-analysis was conducted for surface and indoor temperature for each intervention/comparison group for landscape and building modifications, and descriptive analysis was performed on human outcomes for individual-level interventions due to wide variability in reporting of outcomes. Results The meta-analysis suggests that green roofs significantly reduced surface temperatures by 10.88°C (95% CI: −15.26°C to –6.50°C) and indoor temperatures by 2.4°C (95% CI: −3.54°C to –1.26°C) compared with conventional roofs. Green walls significantly reduced surface temperatures by 2.39°C (95% CI: −4.03°C to –0.74°C) and indoor temperatures by 2.08°C (95% CI: −3.00°C to –1.16°C) compared with bare walls. Pavements with modified asphalt materials reduced surface temperatures by 5.45°C (95% CI: −6.75°C to –4.15°C) compared with conventional asphalt. Reflective paints significantly reduced surface temperature by 4.55°C (95% CI: −6.74°C to –2.36°C) and indoor temperatures by 1.69°C (95% CI: −3.35°C to –0.02°C) compared with conventional roofs. Most studies examining heat action plans reported a decrease in mortality, and heat education and heat warning systems led to reduced morbidity and mortality and improved heat-related knowledge, attitudes and practices. Studies have reported physical strain alleviation and improvement in body temperature while using modified garments. Conclusions With the increasing exposure to extreme heat, contextual evidence will provide valuable insights for effectiveness, acceptance and cost-effectiveness for various interventions.

Behavioral and thermoregulatory responses of dairy heifers under different roofing materials in a humid tropical climate

Understanding how dairy heifers respond to different roofing materials in humid tropical climates is critical for improving their welfare and productivity. This study analyzed dairy heifer’s behavioral and thermoregulatory responses under different roofing materials in a humid tropical climate. The study involved five growing heifers, each under two years old and averaging 210 kg in body weight. Two roofing materials were tested: a conventional roof (CR) made from asbestos and a modified roof (MR) constructed with layers of UPVC, aluminum foil, and rock wool. The heifers underwent a two-week adaptation in CR, followed by one week of data collection. They then transitioned to MR for another two weeks of adaptation and subsequent data collection. The data collected included behavior observations (lying, standing, and lying bout frequency) and thermoregulatory responses (rectal temperature, respiration, and heart rate). The results showed that the average lying and standing time behaviors were differed significantly between two roof materials (p<0.05). The ambient temperatures tended to be lower in MR, especially during noon and the afternoon. Roof surface temperatures were significantly reduced by 27–32% (p<0.05) compared to CR. The study indicated mild to moderate heat stress, with overall means showing significant differences in rectal temperature, heart rate, and respiration rate (p<0.05), consistently lower in MR than CR. Modifying roof materials demonstrates a better microenvironment, improves the comfort and productivity of heifers under humid tropical climate and is important for sustainable dairy production in tropical regions.

Impact of an Aged Green Roof on Stormwater Quality and First-Flush Dynamics

Green roofs (GRs) are increasingly implemented for stormwater management, and retrofitting conventional roofs is emerging as a key strategy for climate change resilience. However, their impact on diffuse pollution, particularly regarding total organic carbon (TOC) and pollutant mass transport, remains insufficiently understood, especially in aged substrates. This study evaluated and compared the runoff quality from aged GRs and ceramic roofs (CRs) by analyzing TOC, pH, electrical conductivity (EC), first-flush occurrence and intensity, and pollutant release patterns. Results showed that GR retrofitting could help mitigate acid-rain effects due to its elevated pH. Despite higher TOC and EC concentrations in runoff, GRs remained within acceptable water quality limits and exhibited a more gradual release of organic matter over time compared with CRs. Statistical analysis revealed that pollutant concentrations in CR runoff followed Lognormal and Weibull distributions, while GR runoff was best described by Normal, Lognormal, and Weibull distributions. These findings reinforce GRs as a viable stormwater management strategy but highlight the need for full runoff treatment when used for rainwater harvesting. The results also emphasize the importance of tailored statistical models to enhance runoff predictions and optimize GR performance in urban water management. The results provide valuable insights for urban planners and policymakers by reinforcing the potential of GRs in stormwater quality management and supporting the development of incentives for green infrastructure. Future research should expand to different GR configurations, climates, and maintenance practices to enhance the understanding of long-term hydrological and water quality performance.

Integrating 3D-printed clay formwork into thin-vaulted green roof

Green roofs (GRs) play an important role in urban sustainability initiatives, offering reduced building energy consumption and enhanced ecological performance through additional growing medium and vegetation layers. Nevertheless, these functional components introduce challenges such as extra structural load, greater slab thickness, and increased construction complexity. This research proposes a design-fabrication method for a thin-vaulted green roof prototype, featuring a compression-only surface and upstand ribs along unevenly distributed stress lines to achieve both lightweight properties and material efficiency compared to a conventional flat roof with GR systems. To realize such a non-standard and multifunctional structure, a hybrid formwork system combining 3D clay printed (3DCP) molds and a reusable, doubly curved foam base is proposed to handle geometric complexity and functional integration by incorporating stay-in-place formwork as the growing medium. An empirical construction experiment, conducted at a 1:5 scale, validates the proposed method with optimized fabrication procedures for a proposed application scenario in a community renovation project.

Enhancing Urban Resilience: Stormwater Retention and Evapotranspiration Performance of Green Roofs Under Extreme Rainfall Events

Rapid urbanisation and climate change have intensified extreme rainfall events, exacerbating stormwater runoff and overwhelming urban drainage systems. Nature-based solutions, such as green roofs with integrated retention capacity, offer promising strategies to mitigate these challenges. This study investigates the influence of substrate thickness and retention volume on the stormwater retention and evapotranspiration (ET) performance of three green roof variants under extreme rainfall scenarios (natural and 5-, 30- and 100-year events). Using lysimeter-based experimental setups, we show that the overall retention capacity is highly dependent on the filling status of the retention layer. Near full capacity, retention performance decreases significantly, resulting in runoff behaviour similar to that of conventional green roofs, while empty systems store up to 99% of rainfall. In addition, ET rates tend to decrease in systems with higher substrate layers and larger retention spaces due to reduced surface evaporation and greater thermal insulation. However, higher substrate layers store more water, allowing plants to maintain transpiration during dry periods, potentially increasing total cumulative ET over time. Overall, this study highlights the importance of designing intensive retention green roofs with dynamic water management to optimise both rainwater retention and ET, thereby increasing urban resilience to increasing rainfall extremes caused by climate change.

Effects of conventional, extensive and intensive green roofs on seismic performance of SMRF structures by endurance time method

Effects of conventional, extensive and intensive green roofs on seismic performance of SMRF structures by endurance time method

Analisis Kualitas Genteng Beton Eco-Friendly dengan Cocofiber dan Cangkang Telur Ayam Sebagai Substitusi Pasir dan Semen

One of the building construction materials needed is concrete tile for the roof of the building. However, concrete tiles have disadvantages, namely a higher price and heavyweight compared to other types of tiles. Therefore, innovations are needed to overcome these problems. This research utilizes coconut coir fiber waste with the same content as sand, which contains 30% silica fiber and is pozzolanic. Then, eggshell waste will be used as a substitute for cement because it contains the same compounds as cement, namely magnesium, iron, and calcium carbonate. The variations in the composition of coconut fibers and eggshells in the manufacture of concrete roof tiles as a partial substitute for the use of sand and cement are GA (0%: 0%), GB (34%: 6%), GC (40%: 6%), GD (32%: 8%), and GE (38%: 8%). In this study, the flexural strength test, water absorption test, water seepage resistance, as well as analyzing the weight and cost of concrete roof tiles were tested. The results of the most optimum concrete tile test are in the GD sample variation: a flexural load value of 1858.2 N, a porosity value of 8.53%, and a seepage test with no water droplets. Then, for the weight analysis of the GD variation, the concrete tile weighs 4.39 kg, and the production cost is IDR 3,017.00. The price differs from conventional roof tiles, Rp 611.00 or 16.84%. The test results show that it fulfilled SNI 0096: 2007.

The Global Warming Potential of Geoengineering via Radiative Cooling

Abstract This paper analyzes the potential to mitigate global warming using radiative cooling (RC) surfaces on a large scale. The study evaluates the net cooling power, radiative forcing (RF), and global warming potential of different RC materials compared to conventional construction and roofing materials, Earth's natural surfaces, and some reference cases. Key parameters for evaluating the above‐mentioned structures include their solar reflectance (albedo) and long‐wavelength infrared emissivity. Results show the cooling power that can be achieved by an ideal RC material with a solar reflectance of 100% and long‐wave infrared emissivity of 100% is 164.8 W·m−2. In practice, materials exhibiting a cooling power as high as 160.8 W·m−2 are fabricated. Further analysis shows if 1% of Earth's surface are to be covered with this material the terrestrial RF will decrease by 1.61 W·m−2 (from 0.6 to −1.01 W·m−2). The results demonstrate that RC materials with high solar reflectivity and emissivity offer substantial cooling benefits and can reduce RF when implemented on large scales. The findings underscore the effectiveness of RC materials in reducing global warming and provide a valuable perspective on their role in reducing the environmental impacts of the built environment.

Rock mineral wool–based green roofs to improve the quality of urban water runoff

Green roofs are nature-based solutions that allow greenery to be integrated into the building envelope, making it possible to re-nature cities while providing multiple benefits. However, whether green roofs are a source or sink of pollution in the urban environment is still a controversy. One of the causes of the possible deterioration of the quality of runoff water from green roofs is the substrate. Green roofs based on rock mineral wool (RMW) growing media require thinner substrate layers or can even be substrate-less. In the present study, four green roof systems based on RMW have been studied over the course of 2 years. Their performance, in terms of leachate quality, has been compared with two traditional roofs, a green roof with pozzolana as a draining material and a gravel-ballasted conventional flat roof. Limit values for wastewater quality from international regulations were considered benchmark. The main conclusions were that after the first flush, which was observed for all solutions, generally exceeding the limit values, RMW-based solutions performed better than traditional solutions. Furthermore, the average values of leachates from all tested green roofs and especially those from RMW solutions fall within the limits set by international regulations.

Optimisation of Embodied Carbon and Thermal Performance of Roof Material Selections for Australian Residential Housing

This research is responding to the latest sustainable development policy for residential housing in Australia, which mandates a minimum R6.0 for roof insulation and a requirement of reporting the embodied carbon footprint for new build residential houses before obtaining development approval. The requirement of thermal resistance (R-value) results in thicker roof material to be used, and inevitably increases the total embodied carbon. This condition has drawn the need for an optimised design to balance the embodied carbon with the required thermal performance. In this paper, a multi-objective, mixed-integer, non-linear mathematical programming model is adopted to perform the optimisation. While mathematical programming is a well-established method in optimisation, a research gap has been observed in its application in optimising roof material selection under the simultaneous constraints of the R-value and volumetric heat capacity (thermal mass). Using a common conventional pitched roof with a timber frame, the study demonstrates how the model identifies material combinations that minimise the total embodied carbon within the specified thermal performance ranges. The unique contribution of this research is integrating thermal mass into the optimisation of roof material selections alongside thermal resistance, and embodied carbon. The findings provide practical recommendations for sustainable material selections across varying R-value and thermal mass ranges, offering a new perspective on roof material selections.

Seasonal diversity, daily use and behaviour of birds using a green roof in a Mediterranean city.

Urban green roofs offer environmental and social benefits and provide resources for urban wildlife; however, how birds use green roofs remains poorly studied in Mediterranean cities. Here, we develop a 1-year study in Madrid, Spain, recording the birds that use both an urban green roof and the adjacent conventional roofs throughout the four seasons. We recorded a total of 17 bird species in the area, of which 8 use the green roof surveyed. The most common species detected in both types of roofs was the feral pigeon (Columba livia), which exploited the green roof permanently, in contrast with the other species observed, which only appeared occasionally. We also found that more species visited the green roof in the central hours of the day and a higher richness of species in the spring. Moreover, we detect that most of the species were residents all year in the area and have granivorous or granivorous-omnivorous feeding habits. The main behaviour observed in the green roof was feeding, while no reproduction of any species was confirmed. We conclude that green roofs offer birds much-needed resources in metropolitan areas, promoting greener, more connected and more biodiverse cities.

Green roof runoff reduction of 84 rain events: Comparing Sedum, life strategy-based vegetation, unvegetated and conventional roofs

Green roofs have emerged as effective stormwater management systems, but understanding the contribution of their various components to hydrological performance is crucial for optimizing their design and implementation. More empirically measured data on the hydrological function of green roof vegetation is needed, especially under realistic low-maintenance, non-irrigated scenarios. Further, targeted, evidence-based plant selection based on ecological theories may improve green roof hydrological performance. Previous research has suggested that, in contrast to monocultures, mixtures of species with complementary traits could optimize provisioning of various ecosystem services. Thus, species mixtures based on their adaptive life strategy using the CSR theory (Competitor, Stress tolerator, and Ruderal) were hypothesized to have better hydrological performance than a Sedum monoculture or bare substrate under natural conditions over multiple seasons. To test this hypothesis, the runoff from thirty 2 m2 green roof modules was measured. The retention and detention performance of different green roof treatments were evaluated for 84 precipitation events of varying rain depth and intensity during snow-free periods. Differences in retention as well as detention between the vegetation treatments varied, but generally increased with increasing rain event volume and the Stress-tolerant treatment generally performed better than bare substrate. On a mean event basis, the mixture of stress-tolerator species demonstrated a 74 % retention rate, while the Bare substrate retained 72 % of the rainfalls. Overall, the green roofs, including bare substrate and vegetated treatments, effectively retained >50 % of the cumulative precipitation depth. In line with previous studies, the Sedum monoculture generally showed worse hydrological performance than other non-succulent vegetation mixtures, despite its relatively high cover and survival. The vegetated treatment with the highest species richness and diversity in life strategies (Mix) did not provide the best vegetation cover, or hydrological performance. Instead, the Stress-tolerant treatment, characterized by the high survival rate of a single graminoid species, consistently demonstrated superior event-based stormwater retention and peak attenuation capabilities.

Application of PV on Commercial Building Facades: An Investigation into the Impact of Architectural and Structural Features

The rapid global transition toward renewable energy necessitates innovative solar PV deployment strategies beyond conventional roof installations. In this context, commercial building facades represent an expansive yet underutilized resource for solar energy harvesting in urban areas. However, existing studies on commercial rooftop solar PV predominantly focus on European contexts, neglecting the unique design constraints and performance trade-offs present in regions such as the Middle East. This study addresses this gap by specifically investigating the impact of architectural and structural features on the utilizable facade area for PV deployment in commercial buildings within the hot desert climate of Saudi Arabia. Detailed case studies of twelve representative buildings are conducted, combining architectural drawing analysis, on-site measurements, and stakeholder surveys. The methodology identified sixteen parameters across three categories—facade functionality, orientation suitability, and surrounding obstructions—that impose technical and non-technical restrictions on photovoltaic integration 3D modeling, and irradiance simulations revealed that, on average, just 31% of the total vertical facade area remained suitable for PV systems after accounting for the diverse architectural and contextual limitations. The study considered 698 kWh/m2 of solar irradiance as the minimum threshold for PV integration. Shopping malls displayed the lowest utilizability, with near-zero potential, as extensive opaque construction, brand signage, and shading diminish viability. Offices exhibited the highest utilizability of 36%, owing to glazed facades and unobstructed surroundings. Hotels and hospitals presented intermediate potential. Overall, the average facade utilizability factor across buildings was a mere 16%, highlighting the significant hurdles imposed by contemporary envelope configurations. Orientation unsuitability further eliminated 12% of the initially viable area. Surrounding shading contributed an additional 0.92% loss. The results quantify the sensitivity of facades to aspects such as material choices, geometric complexity, building form, and urban context. While posing challenges, the building facade resource holds immense untapped potential for solar-based urban renewal. The study highlights the need for early architectural integration, facade-specific PV product development, and urban planning interventions to maximize the renewable energy potential of commercial facades as our cities rapidly evolve into smart solar energy landscapes.

Development of PCM tile for residential buildings in hot and dry climate: design and optimization

In recent years, the building sector has become more conscious of sustainability, and the use of phase change materials (PCMs) in concrete has gained more attraction. Integration of PCM with building facades is a successful method to reduce energy consumption and improve human comfort. However, no single PCM can work in an all-weather scenario. Hence, in this research work, an attempt is made to select a suitable PCM for Chennai city, India, and this methodology can be employed at any geographical location. The PCM tile is designed by including certain features to increase the thermal conductivity of the PCM zone. The optimum design of the PCM tile is achieved through multi-objective optimization techniques. L27 orthogonal array is employed, and all the tests were conducted through validated numerical simulation. Redesigned PCM tile includes a PCM layer of 2 cm thickness with a 10% mix of copper nanoparticles covered by plaster. Redesigned PCM tile reduces the peak indoor temperature by 6.62℃ compared with conventional roof systems.

Innovative silica aerogel fiberglass walls and roofs: A path to lower carbon emissions and higher energy savings

ABSTRACT Buildings account for a significant portion of global energy use and consumption. Buildings have substantial energy consumption due to the use of heating, ventilation, and cooling systems. It is evident that the insulation materials used in the design of building envelopes can efficiently reduce the cost of air conditioning by reducing external heat gains and losses. Additionally, the use of environmentally friendly and cost-effective can be beneficial from an environmental standpoint. This paper aims to evaluate the potential for cost savings in the air conditioning of buildings incorporated with silica aerogel fiberglass insulation in hollow concrete bricks (wall) and hollow roof tile (roof). Silica aerogel fiberglass insulation is extensively used for heat insulation purposes, including building insulations, due to its superior thermal insulation and flame retardant properties. The thermo-physical properties of silica fiberglass insulation and building materials were determined experimentally as per ASTM D 5334 standards. Twenty distinct building design concepts are investigated in this study, each featuring insulation-integrated concrete blocks composed of silica aerogel fiberglass: (WEM1) insulation layer in the outer side, (WEM2) insulation layer in the center, (WEM3) insulation layer in the inner side, (WEM4) insulation layers in the outer-middle, (WEM5) insulation layers in the middle-inner, and (WEM6) insulation layers in the outer-inner sides. Additionally, two arrangements of insulation-stuffed roof tiles, REM1 above the RCC and REM2 below the RCC. In addition, novel building designs integrated with insulation were analyzed numerically, related to environmental conditions that refer to two different scenarios in India (hot dry and composite climates). Thermo-economic analysis of novel wall and roof designs with silica fiberglass insulation materials on air-conditioning costs, carbon dioxide emissions, and payback time are compared with conventional roof and wall patterns. The thermo-economic analysis was carried out based on the number of degree-hours of heating and cooling to determine the building’s annual energy usage. The building model arrangement (WEM6-REM1), which consists of an insulation composite wall (WEM6) and insulation roof tile (REM1), demonstrated the greatest annual air conditioning cost savings of 3.4 $/m2/year and 1.74 $/m2/year when compared to conventional building design for climatic conditions of Kurnool and Gauhati. The building model arrangement (WEM6-REM1) composed of silica fiberglass aerogel insulation exhibits the highest reduction in carbon emissions of 65 kg/kWh and 33 kg/kWh, when compared to conventional building design analyzed in both hot-arid; (Kurnool) and composite (Gauhati) climatic conditions. The placement of insulation in the roof alone (REM1) has the shortest payback duration of 2.15 years. The results of this study point to a viable approach to enhancing building design decision-making and narrowing the performance gap in sustainable and energy-efficient strategies.

Selection of tropical plants for an extensive green roof with abilities of thermal performance, energy conservation, and greenhouse gas mitigation

Selection of tropical plants for an extensive green roof with abilities of thermal performance, energy conservation, and greenhouse gas mitigation

Enhancing the building resilience in a changing climate through a passive cooling roof: A case study in Camas (Seville, Spain)

Renovating buildings is a crucial mission for the coming decades to combat energy inefficiencies and produce a resilient building stock. The inefficient thermal envelope has significant implications for occupants, especially for families lacking the financial resources to maintain a healthy and comfortable indoor environment. In scenarios where households cannot afford or utilize HVAC systems and high temperatures are more frequent, building retrofits should prioritize reducing heat loss in winter and passively lowering indoor temperatures in the cooling season. This work introduces a new solution to enhance the liveability of a social housing building in southern Spain by integrating a double-skin roof with a conventional retrofit strategy, which incorporates passive cooling techniques – night ventilation and an evaporative cooling system – for effective heat dissipation based on available commercial solutions. An extensive monitoring campaign was conducted over three years to evaluate the thermal comfort of occupants and the risk of overheating in naturally conditioned buildings before and after renovation following two impact assessment methods: real-time data-based and simulation-based. The real-time data-based method compared the indoor conditions of a dwelling with a conventionally retrofitted roof to one with a double-skin roof, indicating that the dynamic roof maintains a ceiling temperature lower than the air temperature throughout the summer while the conventional roof acts as a heating surface. On the other side, the simulation-based method compared the observed indoor conditions with a double-skin roof enabled during 2023 to the initial stage and a double-skin roof disabled scenario, using calibrated building energy models. The natural cooling roof solution almost eliminates the overheating events, leading to a reduction of 94.1% and 76.9% in discomfort degree-hours compared to the initial stage according to the ASHRAE adaptative and Fanger comfort models, respectively. Additionally, the results indicate that conventional retrofits can increase the risk of overheating when a cooling system is not considered. Integrating a cool roof solution requires only an extra implementation cost of 31€/m2 compared to a conventional solution, having an operational cost that represents less than 3% of the minimum monthly income in the social housing district.

Contemporary roof pattern for energy efficient buildings: Air conditioning cost alleviation, CO2 emission mitigation potential and acceptable payback period

Contemporary roof pattern for energy efficient buildings: Air conditioning cost alleviation, CO2 emission mitigation potential and acceptable payback period

Smart roofs featuring predictive control: An upgrade for mitigating precipitation extreme-induced pluvial floods

Smart roofs featuring predictive control: An upgrade for mitigating precipitation extreme-induced pluvial floods

Adaptacija postojećih ravnih krovova solitera u zelene krovove na području Općine Kakanj u cilju osnaživanja i promovisanja koncepta urbane poljoprivrede

The Municipality of Kakanj, an industrial municipality, emphasizes the crucial importance of environmental preservation, development encouragement, and the improvement of urban agriculture. In urban planning, a return to fundamental values aligned with population needs is essential. Urban spaces should encompass functions related to housing, livelihoods, social utility, and interaction. However, the issue arises with the reduction of green areas due to building construction, causing a disconnect between people and nature in their fast-paced urban daily lives. For this reason, green roofs on residential buildings are one way for residents to have daily contact with greenery, ultimately promoting a healthier and more active lifestyle. The creation of green roofs often provides the opportunity for urban beekeeping (depending on the location), which has been considered one of the solutions to the bee extinction problem and the increase in pollinators in recent years. The aim of this project is to develop a conceptual plan for adapting the existing flat roofs of three towers (S-1, S-2, S-3) built in the 1980s in the Municipality of Kakanj into green roofs. These green roofs will create the potential to strengthen and expand the importance of urban agriculture, bringing a range of ecological, social, and economic benefits. This project seeks to redefine the skyline by replacing conventional roofs with lush green roofs, nurturing a harmonious blend of nature and urban life.