Roofing Materials Research Articles

Identifying influential architectural design variables for early-stage building sustainability optimization

Architectural design variables (ADVs) highly influence a building's sustainability performance. Thus, identifying which ADVs are most influential in a building's early stages is of great significance, especially when using computational building design optimization tools. Currently, sensitivity analysis based on computer simulations is the most commonly used means to identify which ADVs are the most influential in the early stages. However, we suggest that a stakeholder perspective should also be considered as stakeholders possess domain-specific knowledge and expertise as well as a contextual understanding that can greatly enhance the development and deployment of building design optimization tools. To explore the above, we combined a literature review with survey data from 24 architects and sustainability consultants in the Nordics. Surprisingly, we found that the influential ADVs in the literature do not always align with those of our surveyed stakeholders. For example, we found that the literature considers building plan, window-to-wall-ratio (WWR), and wall material as the most influential ADVs, which contrasts with storey number, storey height, WWR, roof material and wall material considered by stakeholders to be the most influential. We also found that the most influential ADVs differ across different sustainability optimization objectives, and that these also differ from the literature. Despite our limited survey sample, our study provides insights into influential ADVs and as such has implications for the development, use, and performance of computational building design optimization tools.

Importance of Bamboo for Immediate Earthquake Recovery: A Study from Nepal

This study was conducted in four districts of Nepal, Sindhupalchok, Gorkha, West Rukum and Jajarkot. It analyzed the importance of bamboo in immediate earthquake response and recovery. A total of 464 respondents were sampled from four districts struck by earthquakes. 83% of the households had bamboos on their own land, as well as trees such as Pinus spp., Castanopsis spp. and Schima wallichii. 85% of the households used bamboo for pillars, poles, and other supporting materials to hold and adjust roofing and wall materials during the time of the disasters. Moreover, 96% households believed that bamboos were highly useful and thus significant during the time of disasters such as earthquakes. People were aware of the importance of bamboo for coping with disasters; however, they were lacking appropriate knowledge about the socio-economic and environmental significance of bamboo species due to limited knowledge and research.

Are Microstructures in Plutonic Rocks Primary or Secondary? A Re-examination of the Metasomatism Hypothesis for the Roof-Sourced Autoliths in the Skaergaard Intrusion

Abstract The roof-derived autoliths in the floor cumulates of the Skaergaard Intrusion have been argued to have been extensively metasomatised and recrystallised, forming the foundation of the hypothesis that microstructures in plutonic rocks are essentially metamorphic. However, the augite–plagioclase–plagioclase dihedral angles and plagioclase core composition of the autoliths match with those of the roof rocks, demonstrating that they were generally solid on arrival at the floor, with no subsequent microstructural or compositional modification. Many autoliths have mafic rinds, which were used as evidence of metasomatism: these rinds fall into two groups. The rarely developed rind rock of Irvine et al. (1998) is most likely chilled magma infiltrating along fractures in the roof rocks, either associated directly with detachment of roof material, or occurring before final detachment. Thin mafic rims are widespread in LZc and MZ, present at the tops of the more elongate autoliths, with a corresponding felsic rim at the base of the most elongate autoliths. The close correspondence of thin rim development with autolith shape, rather than composition, is argued to be evidence that they formed as a result of differential migration of immiscible conjugate interstitial liquids: the dense Fe-rich liquid flowed downwards and ponded on the tops of impermeable autoliths, whereas its buoyant Si-rich conjugate flowed upwards and was trapped underneath. Any differences in microstructure and bulk composition of the autoliths compared with the remaining exposures of the roof sequence reflect the wider range of lithologies in the now-eroded regions of the roof.

Preservation or Revitalization? Examining the Conservation Status and Destructive Mechanisms of Tulou Heritage in Raoping, Chaozhou, China

ABSTRACT Tulou is an ancient and remarkable residential heritage that has garnered global attention for their distinctive form and spatial layout that serves both defensive and settlement purposes. This paper provides a comprehensive analysis of the current preservation status of tulou, based on a field investigation of 83 officially recognized cultural relic protection units and immovable cultural relic tulou in Raoping County, Chaozhou City, Guangdong Province. This study focuses on primary damage conditions such as adding doors and windows on external rammed earth walls, replacing roofing materials, additional construction and overall reconstruction, while also revealing the mechanism of hollowing destruction. The study proposes utilizing the “Rural Revitalization” initiative, which is currently being vigorously advocated by the government, as an opportunity to introduce diversified functions into the protection and revitalization of tulou buildings. This will ensure that the tulou are preserved to their fullest extent while also allowing them to continue serving contemporary community life and establishing a new spiritual connection with modern-day villagers. This study offers realistic and comprehensive insights into the current state of tulou heritage preservation, as well as active and effective guidance for preserving and renovating not only tulou but also other residential architectural heritage around the world.

Sustainable Material Selection in New Constructions: A Brute‐Force Optimization Framework Using Parallel Computing, Cost Benefits, and Thermal Performance Analysis

Sustainable construction practices rely on carefully selecting building materials and balancing environmental and economic considerations. This study examines the complex link between local climate, market dynamics, and building material selection. Market data analysis, parametric modeling, and brute‐force optimization are used to provide insights into construction decision‐making. Across 5540 simulations, a thorough assessment of the financial and energy performance of various materials for walls, roofs, windows, and floors is conducted. Incorporating Pareto ranking, parallel simulation, and sensitivity analysis, the comprehensive evaluation reveals the intricate tradeoffs between cost, thermal properties, and energy savings. The findings highlight the potential for optimal external wall solutions to reduce U‐values by up to 30% and achieve source energy savings of up to 25% source energy savings across diverse climates. By emphasizing the importance of local context in material selection, this study highlights how energy consumption patterns and transmission losses influence financial and energy performance, thus advancing sustainable construction practices.

Survey on green roofs in Poland

The aim of this paper is to present the results of a survey on green roofs among potential real estate developers and users, concerning knowledge about, awareness of the benefits of, and interest in green roofs. The survey sample consisted of 151 persons – potential owner-builders from Poland. This is not a large number, but it is significant. The research sample was purposive and statistically insignificant, and the study was an initial part of a larger project. Greenery in urban settings positively affects human quality of life and health and contact with nature improves well-being and reduces stress. Roofs covered with greenery are also a sign of growing environmental awareness. In Poland, green roofs are usually a feature of public and commercial buildings. The low popularity of this solution in single-family housing has its source in potential owner-builders being unaware of the benefits of the roofs’ application, funding opportunities, and benefits in the form of a greater amount of biologically active surfaces. Currently, the technology of covering roofs with greenery is highly developed, and there are many experienced contractors who operate on the Polish market. However, there is a deficiency in knowledge about green roofs among real estate developers and prospective owner-builders, which constitutes a demand barrier. Many people are anxious about using a green roof out of fear of high construction costs and necessary greenery maintenance. This is due to misinformation, as it is possible to use an extensive, low-maintenance roof type. In the case of an intensive roof, the maintenance largely resembles that of a traditional domestic garden. The costs of creating a roof garden are higher than in the case of traditional roofing materials, but a smaller plot could be bought as a result, as a greater amount of biologically active surfaces can be obtained to meet zoning regulations. In Poland, there are currently no legal regulations that obligate or incentivise the use of green roofs. The popularity of this solution is growing, which gives hope for making cities greener. In an era of progressing climate change, building additional green spaces, including those on roofs, is a crucial remedy for the severe consequences of unsustainable urbanisation.

Roofing systems and energy efficiency in low-rise buildings: A comparative study across India’s diverse climates

The building envelope is the interface between the external atmospheric conditions and the indoor environment. It contributes to approximately 60%–70% of the heating and cooling load. The building envelope constitutes walls, fenestrations, and roofs from which thermal transfer from the roof is significantly very high compared to walls in low-rise buildings.This research paper aims to provide recommendations for energy-efficient roof design considering roof form, material, and external coating suitable for various climate conditions of India. The paper’s methodology consists of a literature review of related research papers, learnings from the roofing system of energy-efficient building case studies, and all possible energy-efficient roofing systems that would be simulated for energy efficiency and thermal comfort in five climate types of India. The expected outcome of this paper would be in the form of recommendations for roofing systems in different climate type and their potential for energy saving from the highest to the lowest. This research would be done in three stages viz, Step-1: Literature Review and case study of best practices: A review of the related literature and best practices examples would be done to formulate the maximum possible cases for the simulation. Step-2: The roofing systems, including building form, material (Thermal and insulation), and finishes (reflectance), would be simulated one by one for various climate types of India (composite, hot & dry, warm and humid, moderate and cold) to optimize energy efficiency and payback period. Step-3: Special roof types like Green roofs, cool roofs, Photovoltaic roofs, roof ponds, and the like are simulated and compared for their effectiveness in selected climate types. Based on the literature review, simulation results, and analysis, the recommendations are framed for energy-efficient roofing systems in the selected climate type with respect to heat transfer through the roof and thermal comfort.

Bio and waste-based binders with hybrid rubberized-thermoplastic characteristics for roofing

Non-bituminous binders with sustainable characteristics have been developed as potential roofing materials. A vegetable colophony rosin ester, waste cooking oil, waste crumb rubber and a blend of recycled high-density polyethylene (HDPE) and polypropylene (PP) have been used for binder formulations. Rheological, calorimetric and technological characterizations have been performed to assess the compatibility among binder components and optimal compositions. Additionally, thermal conductivity, heat capacity and solar radiation tests have been performed on selected non-bituminous and bitumen-based binders. Solar radiation experimental set-up has been simulated by Computational Fluid Dynamics (CFD) in order to get a deeper insight into heat transmission mechanisms involved. A binder formulation composed of 40 wt% maleic-modified rosin ester, 32 wt% waste oil, 20 wt% crumb rubber and 8 wt% recycled HDPE/PP blend has shown suitable mechanical properties and solar behaviour for roofing materials. The use of recycled thermoplastics and elastomers imparts material with a hybrid character, showing enhanced flexibility and softening points, respectively, at low and high in-service temperatures. Its solar behaviour is comparable to that of the modified bitumen, with a similar heat absorption from Sun (about 30 %) but lower heat storage capacity at ambient temperature.

Research on energy-saving renovation of solar greenhouses based on multiple factors and multiple objectives

The applicability of the traditional energy-saving renovation method for greenhouses is limited and influenced by the subjective decisions of researchers. Therefore, in this paper, a multifactor and multiobjective unbiased evaluation method is proposed based on the orthogonal test and entropy methods to study energy-saving transformation of solar greenhouses. The results show that the thickness of the gas layer, type of front roof glass and thermal insulation material of the rear roof greatly influence energy consumption, accounting for 45.5 %, 34.4 % and 15.3 %, respectively, of the total energy consumption, followed by the type of gas, thickness of glass and thermal insulation material of the heat storage wall, accounting for 3.2 %, 1.1 % and 0.5 %, respectively, of the total energy consumption. Based on energy savings, carbon emission reduction, investment cost and payback period, all renovation cases are comprehensively analyzed by the entropy weight method. The results show that Case m is the best renovation case, i.e., the front roof comprises three-layer glass, the glass thickness is 3 mm, the width of the cavity is 6 mm, which is filled with krypton gas, the rear roof insulation material is 100-mm thick extruded polystyrene (XPS), and the heat storage wall insulation material is 100-mm thick expandable polystyrene (EPS). This renovation method provides a systematic and objective theoretical basis for energy-saving renovation of solar greenhouses in cold regions.

An Analysis of the Influence of Cool Roof Thermal Parameters on Building Energy Consumption Based on Orthogonal Design

An analytical hierarchy model of the impact of solar reflectance, thermal emittance, heat transfer coefficient, and heat storage coefficient on building energy consumption was established through the implementation of orthogonal design experiments. The EnergyPlus software (v9.0.1) was utilized to simulate building energy consumption across diverse climatic regions in China, providing essential benchmarks for the orthogonal design. The results of the range analysis consistently indicate that, barring regions characterized by extremely cold climates, solar reflectance emerges as the predominant factor exerting an influence on building energy consumption. As geographical latitude increases, the impact of the heat transfer coefficient becomes progressively larger, while the weight of thermal reflectance concurrently diminishes. Drawing upon the principles rooted in the gradient refractive rate theory and the concept of atmospheric window radiation, a range of high-reflectance and high-emittance cool roof coatings in various colors were meticulously developed. A spectrophotometer was employed to precisely quantify their reflectance properties, and simulations were subsequently conducted to scrutinize their energy-saving characteristics. The results demonstrate that the cool roof coatings that were developed using the methodology described in this paper exhibit substantial enhancements in reflectance, with increases of 0.24, 0.25, 0.37, and 0.35 for the yellow, red, blue, and green cool roofing materials, respectively, in comparison to conventional colored coatings. Under typical summer conditions, these enhancements translate to significant reductions in roof temperatures, ranging from 9.4 °C to 14.0 °C. Moreover, the simulations exploring the cooling loads for the roofs of differing colors consistently revealed remarkable energy savings. These savings were quantified to be 4.1%, 3.9%, 5.5%, and 5.4%, respectively, when compared to conventional coatings of the corresponding colors. These findings offer valuable insights into strategies for optimizing the energy efficiency of buildings through the application of high-reflectance cool roofing materials.

Low-cost waterborne radiative cooling paint for large scale production and application in buildings

Passive daytime radiative cooling (PDRC) is a cooling technology with no energy consumption and no pollution generation. It emits self-generated heat to outer space using thermal radiation, thus reducing its temperature. Radiative cooling technology aims to the energy consumption problem of buildings and environmental pollution caused by the use of Freon in compressor air conditioners. Many kinds of radiative cooling coatings have been attempted, but the cost and large-scale practical application have been challenging. This work prepared a composite coating with a radiative cooling function using calcined kaolin (CK) powder and waterborne fluorocarbon (WF). The inexpensive CK has a wide particle size distribution and exhibits high solar reflectivity (RS) and infrared emissivity (EIR). The excellent adhesion and chemical stability of waterborne fluorocarbon (WF) provides a good guarantee for the practical use of the coating. As a result, the CK/WF coating achieves an RS of 91% and an EIR of 95% in the transparent atmospheric window (ATW) of 8–13 µm. The coating demonstrated a temperature decline of 3.8 °C under direct sunlight in the field. The coating meets the conditions for large-scale applications. When used as a roofing material for simulation, it can save up to 30% of energy consumption throughout the year. Overall, the CK/WF coating has outstanding energy saving and pollution reduction performance, which will further advance the radiant cooling material into real-world applications.

Eco-friendly green roof solutions: Investigating volcanic ash as a viable alternative to traditional substrates

This research investigates the potential of volcanic ash as a green roof material, focusing on its thermal conductivity, physical characteristics, and permeability. Laboratory tests were conducted to determine thermal conductivity under different moisture conditions using two measurement devices, TLS 100 and HFM 436/3/1 Lambda. The results revealed that thermal conductivity increases with higher moisture content, indicating improved heat conduction as the material becomes more saturated with water. Particle size distribution analysis demonstrated that the majority of volcanic ash particles fall within the range of sand and gravel, providing a porous and well-draining material. Sand-sized particles create interconnected voids, facilitating efficient water movement, while gravel-sized particles enhance structural stability and load-bearing capacity. The limited presence of silt-sized particles further validated the material's suitability for green roof applications. Permeability tests on loosely compacted volcanic ash revealed higher permeability at 0% compaction, aligning with intended green roof configurations. This high permeability ensures effective drainage, preventing water accumulation and promoting healthy vegetation growth. At 20% compaction, the material still effectively managed water under potential compaction forces, striking a balance between drainage and water retention. Visual examination of green roof samples demonstrated that volcanic ash substrates resisted weed growth due to the absence of fertilization. While the commercial substrate exhibited better vegetation development due to added nutrients, volcanic ash substrates supported vegetation survival throughout the summer period with an irrigation system, reducing maintenance and lifecycle costs. In conclusion, the research findings indicate that volcanic ash possesses desirable thermal properties, a suitable particle size distribution, and favorable permeability characteristics for green roof applications. Its potential as a sustainable and cost-effective alternative to commercial substrates is evident, offering resilient urban landscapes with reduced environmental impact. Further exploration and optimization could solidify volcanic ash as a valuable component in advancing green roof technologies, promoting sustainable urban development.

Synthesis and characterization of a pigment with a high near-infrared reflectance: Ca2+-doped Bi2O3

Bi2-xCa3x/2O3 (x = 0.02, 0.04, 0.06, and 0.08) pigments with varying Ca doping levels were made via solid-phase reaction at 700 °C. The outcomes showed that the b* value could be raised from 17.13 to 41.42 by doping with a very modest quantity of Ca (x = 0.02). The pigments that were made have good NIR solar reflectance (84.6%–92.1 %) and a wide band gap (2.56–2.75eV), with the NIR reflectance peaking at x = 0.06. The pigments don't include pricey rare earth elements and are non-toxic. The colored aluminum flakes have an NIR solar reflectance of more than 50 %, which is greater than the typical (30 %) for pigments used as cooling coatings. In order to evaluate the thermal insulation performance of the coating, it was simulated as a roofing material. The findings demonstrate that under identical irradiation conditions, the coating with sample coloration exhibited a decrease in temperature of 2.3 °C in comparison to the coating with commercially available pigmentation, thermal imaging experiments show that the surface temperature of the sample coating is 3.8 °C lower than that of the commercially available coating, indicating that the sample has good heat reflection performance. Additionally, the pigment's firing temperature is low (700 °C), and it has strong chemical stability (ΔE*ab<5).

Experiments on the Thermal Performance and Service Life of Three High-Albedo Roof Materials in Nanjing, China

Abstract The use of high-albedo roof materials is a simple and effective way to reduce roof temperature, conserve electricity required for air conditioning, and ease power shortages. In this study, three common cooling roof materials, namely, white elastomeric acrylic (AC) paint, a white thermoplastic polyolefin (TPO) membrane, and an aluminum foil composite film–covered styrene–butadiene–styrene bituminous (SBS) membranes, were chosen to conduct a nearly 4-yr experiment in Nanjing, China, to study the difference in surface temperatures (ΔTs) between the cooling roof materials and concrete. The results showed that even during heatwaves, ΔTs was only 2.1°C (AC), 3.8°C (TPO), and 7.0°C (SBS) on average and 6.9°–18.2°C to the greatest extent, which was far less than those reported by many studies. The intensity of solar radiation where the cooling roof material is used and the roof material’s albedo contribute to the difference in ΔTs. The initial albedo of the AC was 0.53 and dropped to 0.16 due to rapid aging, which is close to that of concrete, in less than 3 months. The albedo of TPO and SBS dropped to 0.16 after 9 and 4.7 years, respectively. Further, SBS is the optimal choice in terms of cost and performance, costing only USD 0.67 m−2 yr−1. However, its albedo exhibits seasonal fluctuations and is significantly affected by air pollution. In particular, particulate matter settles on the surface, thereby decreasing the albedo. Nevertheless, manual cleaning can recover the albedo, extend service life, and further reduce costs.

Thermal Insulation of Roof using Composite Materials

Due to industrialization and urbanization the temperature is constantly rising day by day. Conventional roofs used by low-income community/society like metal, steel, aluminium, copper, etc will absorb heat and increases room temperature which creates discomfort for the people. Use of natural fibre composites as a roof material are said to have benefits for the environment. There is an expansion in the usage of natural composite materials as it helps to decrease the room temperature and provides the comfort for the users. In this research paper, an attempt will be made to develop composite materials for layering of roof using sugarcane bagasse and polymer. The composite formed by using both waste materials like sugarcane bagasse and polymer will be tested in terms of various parameters like thermal conductivity, tensile strength and impact test.

Wind-driven rain tightness of building-integrated photovoltaics panels

The exposure to wind-driven rain (WDR) is a key factor impacting the performance and the durability of the building envelope. Building-integrated photovoltaic (BIPV) panels are increasingly used as roofing and façade materials, but little information is available on their weather protection performance. Although WDR exposure has been qualitatively investigated in laboratories, only few studies have directly quantified the water intrusion through BIPV. This article presents the results from a WDR laboratory test of a BIPV product, where water intrusion was both qualitatively and quantitatively investigated. Furthermore, as roof integration is the primary function of the studied BIPV panels, the results from the same test performed on another traditional roofing material, i.e., concrete tiles, are described and discussed. The test results showed that the BIPV panels performed better as façade cladding than as roofing material, since no quantifiable water leakages were detected at 90° inclination. At 15° and 30° inclinations, the total water leakages through the BIPV system were around 90% lower than those of the concrete tile roofing. This article’s findings demonstrate that the quantification of water intrusion through BIPV panels is feasible and can provide significant information for further developing and improving the design of BIPV systems as climate screens.

A Thermal Study of Roof Shapes and Materials in Hot Dry Climates: Insights from a Simulation from Rajasthan, India

A Thermal Study of Roof Shapes and Materials in Hot Dry Climates: Insights from a Simulation from Rajasthan, India

Antecedents of marketing climate change adaption construction materials: Evidence from Ghana

Purpose: Climate Change affects all countries in the world. It impacts negatively on the living conditions of humankind, especially livelihood, temperature change, rainfall regime, and rise in tidal waves. Design/Methodology/Approach: The population in the real estate industry. A descriptive design was used, including questionnaires, to gather data. Since the study sought to examine the willingness to purchase accordingly, a logit regression model was used to predict the likelihood that the dependent variable willingness to pay (WTP) equals 1 (rather than 0). Findings: Income level, price of the products, respondent’s age, gender, and availability of policies concerning eco-friendly products and identified associated health risks positively influence respondents’ WTP. The study reveals that in the real estate sector of the Ghanaian economy, there is a positive WTP eco-friendly roofing product; hence, entrepreneurs and investors should take advantage of the urgency to reduce the impact of climate change in Ghana by investing in eco-friendly products for both the real estate and construction sectors of the economy. Recommendations: The results show that any eco-friendly roof material must raise consumer awareness about the effects of climate change and shape consumer perceptions.

Numerical modelling approach for estimation of a yield zone in the face of a deep longwall panel

In the Longwall mining method, the coal face is being supported with two-legged or four-legged shield supports which improve better roof control between the face and canopy tip. The development of load on the face increases with the face retreating rate or the increase of the overhung length behind the shield support and as a result, the coal face tends to yield/fail. The yield/failure zone in the face extends depending on intensity of developed load due to the depth of mining, panel size, height of excavation and geometry of the overhung. The broken coal from the yielded face may fall on the shearer, armoured flexible conveyor (AFC), shield supports or may hit the deployed manpower in the face and causes the face stoppage which in turn results in to the loss of the project. It is therefore, a study is conducted to understand the face yield/failure behaviour considering various geo-mining conditions based on input parameters such as main roof thickness, overhung length, and material type and setting load. This paper develops a unique statistical model to predict the yield/failure zone in the longwall face. For this purpose, a total of fifty-four (54) three-dimensional finite element models in ANSYS software are developed and analyzed considering Drucker-Prager failure criterion.

French Metallic Train Sheds of 1850 to 1930: Structural Specificities and the Evolution of the Restoration Practices

ABSTRACT Surviving historic train sheds constitute a broad and representative sample of metal construction of the period 1850 to 1930 in France. This article gives a historical overview of the life of iron or steel train shed structures and questions what makes them authentic, discussing the validity of some of the restoration choices made since the 20th century regarding heritage preservation. First, the specificities of this architectural heritage are highlighted and compared with other countries and other types of construction. Then, based on extensive archive material held by the French national railway company SNCF, the modifications the metallic structures underwent as restoration projects were carried out are analysed. It appears that the restoration practices significantly evolved between the 1970s-1980s and the beginning of the 21st century, becoming more sensitive to heritage preservation. However, choices regarding roofing materials have an impact on the loading of the structure, while structural interventions change the appearance and the load distribution. This enhances the need to include considerations regarding the preservation of the structure in the early stages of restoration projects.