Search Results (62)

Quantifying moisture transport through building envelope materials is vital for durability, energy efficiency, and healthy indoor environments. Water vapour diffusion resistivity (µ-value) is a key parameter for hygrothermal modelling, moisture control, and mould risk assessment. Globally, data for solid wood species are scarce, and in Australia—despite the rising use of plantation-grown timber—critical hygrothermal properties remain undocumented. To close this gap, this study experimentally evaluated Eucalyptus nitens, a plantation-grown hardwood widely used in Australian construction. Solid-wood specimens prepared from industry-sourced boards were tested at 23 °C and 50% RH using both the wet-cup and dry-cup methods of the gravimetric technique. For wet-cup tests, µ-values ranged from 24 to 33; for dry-cup tests, µ-values ranged from 179 to 273, showing clear variability linked to differences in relative humidity. Experimental issues included surface cupping, sealing integrity, and extended equilibration time during dry-cup testing. These findings provide the first empirical µ-value dataset for E. nitens under moderate-humidity conditions, delivering essential input parameters for hygrothermal models and supporting moisture-safe, energy-efficient design strategies for the broader construction sector. Full article

The inefficient utilization of industrial by-product phosphogypsum, coupled with the increasing global demand for cooling, has spurred the development of sustainable radiative cooling materials. Compared with conventional cooling coatings that primarily rely on expensive synthetic materials or complex fabrication processes, this study provides a promising cost-effective and sustainable route for integrating industrial solid waste valorization with zero-energy cooling technologies. In this study, we fabricated a composite coating (β-HPG@CA/SiO₂@OTS) consisting of β-hemihydrate phosphogypsum (β-HPG), a derivative product of phosphogypsum, cellulose acetate (CA), SiO₂ particles and octadecyltrichlorosilane (OTS) by a facile combination of blade coating and spraying, which exhibited strong solar reflectivity (90.9%), high mid-infrared emissivity (98.7%) and satisfactory superhydrophobicity (157°). The as-prepared composite achieved an ambient temperature drop of 18.7 °C under direct sunlight during sunny weather, achieving a net cooling power of 92.23 W/m². Meanwhile, the composite coating exhibits excellent durability after prolonged immersion in strongly acidic and alkaline solutions, ultraviolet radiation and outdoor testing. Owing to its simple fabrication process and robust cooling performance, this coating shows promise for scalable production and practical outdoor applications, such as building envelopes and equipment enclosures. Full article

The construction sector remains a major contributor to global energy consumption and greenhouse gas emissions. Heat loss through building envelopes plays a key role, especially in regions with long heating seasons. Hollow building blocks are widely used due to their low cost and structural simplicity, but their inadequate thermal insulation requires additional layers of insulation, increasing costs and complicating installation. The production of cement and traditional insulation materials is associated with a high carbon footprint and disposal issues, which conflict with sustainable development principles and decarbonization goals. In contrast to previous reviews that primarily address bio-based insulation in general building envelopes or focus on bioaggregates in concrete mixes, this paper specifically targets the application of biomaterials in hollow building blocks. It emphasizes how bio-based loose-fill and bound fillers interact with the peculiar thermo-fluid behavior of hollow cavities, including natural convection, conduction and radiation. The effects on thermal performance (thermal conductivity, U-value of walls) are analyzed, along with selected aspects of mechanical strength and durability. Gaps in long-term data on biodegradation are identified. Recommendations for selecting strategies depending on climate and design are offered, as well as directions for future research, including numerical modeling of thermal conditions. The results highlight the potential of biomodified blocks for creating energy-efficient and environmentally friendly wall systems. Full article

Despite its potential to enhance construction quality, efficiency, and sustainability, modular construction continues to experience defects that hinder its broader adoption. Understanding and mitigating defects is essential for maximising the sustainability benefits of modular construction by reducing material waste, minimising rework and improving lifecycle performance. Existing research remains fragmented, with limited synthesis integrating defects with their root causes across the project lifecycle. To address this gap, this study investigates defect types, lifecycle-based causes, and mitigation strategies in modular building projects through a PRISMA-guided systematic literature review of 61 peer-reviewed journal articles published between 2015 and 2025 and retrieved from Scopus and Web of Science. Six major defect categories were identified: geometric and dimensional; material and component; joint and connection integrity; envelope performance and durability; structural; and mechanical, electrical, and plumbing (MEP) defects, with geometric and dimensional defects emerging as the most prevalent, accounting for 26.7% of reported cases. Lifecycle root-cause mapping indicates that poor workmanship during on-site assembly is the dominant contributor, accounting for 44.1% of identified root causes, with manufacturing errors (26.8%) and design limitations (13.4%) acting as critical upstream sources. Mitigation strategies cluster into three groups: general recommendations (39% of reported strategies), mainly focusing on low-cost organisational measures such as logistics coordination and workforce training; structured risk-management frameworks (9.1%), including assembly sequencing and tolerance planning; and digital and data-driven technologies (51.9%), such as laser scanning, AI-based inspection, and digital twins, enabling proactive quality assurance across the lifecycle. The study proposes an integrated lifecycle–defect–mitigation framework to strengthen quality governance and advance sustainable modular delivery. Full article

Maintenance is crucial for the durability of the existing building stock and should be perceived as an opportunity to improve the built environment. The implementation of thermal retrofitting measures to the building’s envelope enhances global energy performance, which is economically and environmentally beneficial. Building-related energy consumption during the operation phase is key to tackling carbon neutrality and climate change. Introducing thermal retrofitting within the context of maintenance planning can be cost-optimizing, as it reveals the technical–economic synergy between building pathology and energy efficiency. Maintenance activities and energy demand throughout the building’s service life influence life-cycle costs (LCCs). Decision-making based on LCC awareness is an advantage for owners. This study discusses the impact of implementing an optimal retrofitting solution (ORS), according to different maintenance strategies, on the LCC of an existing single-family home. The ORS comprises the following measures: adding an external thermal insulation composite system (ETICS) to external walls, extruded polystyrene (XPS) panels to the roof, and replacing the existing windows with others with improved thermal performance. The three maintenance strategies involve different complexity levels, concerning the type, number and timing of activities. Moving beyond isolated assessments, this study develops an integrated framework that bridges based on two existing background methodologies, involving optimal thermal retrofitting and condition-based maintenance planning, which, combined with new research, enable the assessment of maintenance, energy and global LCC for a time horizon of 100 years. The evaluation of energy-related LCC is based on simulations. The results indicate that these costs represent the majority of the global LCC. The ORS has a considerable positive impact on energy and global LCC. Adopting a maintenance strategy characterized by fewer planned activities and an earlier schedule of replacement interventions, which determines the implementation of the retrofitting measures, is better in terms of LCC savings. Full article

This research investigates the air permeability and watertightness performance of commercially available windows and doors based on laboratory tests conducted in accordance with the EN 1026 and EN 1027 standards. All tests were carried out under controlled environmental conditions, and the results were validated following relevant ISO procedures to ensure reliability and consistency. The tests are essential for evaluating the air permeability and watertightness of commercial windows and doors to ensure the overall performance, energy efficiency, and durability of the building envelope. The results provided consist of 244 samples (93 doors and 151 windows) tested between 2018 and 2025 in an accredited laboratory complying with EN ISO/IEC 17025. The results show that most doors achieved the highest air permeability class (Class 4) according to EN 12207, with shares ranging from 50% to 80% and exceeding 65% in most years. Window performance was similarly strong, with more than 74% of samples classified as Class 4, indicating consistently high airtightness and compliance with stringent energy efficiency requirements. Watertightness tests revealed that 59% of products were resistant to water penetration, while 41% were permeable. Among watertight products, windows predominated (67%), while doors accounted for a larger share of water-permeable cases. The results support informed decision making in manufacturing, construction practices, and early-stage building design, contributing to improved building durability and energy efficiency. Full article

The construction sector faces environmental challenges related to material consumption, waste generation and energy efficiency. In this context, light-transmitting concrete tiles incorporating recycled glass offer a favourable solution for the construction of lightweight building envelope systems combining circularity, functional performance and design value. This research project developed novel self-compacting high-performance concrete tiles integrating coarse waste-glass aggregates to develop translucent components for use as solar filters. To the authors’ best knowledge there is a gap in the market regarding this type of envelope. Three concrete mixtures were developed, including the reference mix and two waste-glass-based mixtures with different glass contents, colours and nominal size distributions. Concrete tiles with thicknesses between 4 and 20 mm were analysed regarding their overall physical, mechanical, durability and luminous performance. This research paper’s conclusions confirm the suitability of recycled glass concrete tiles for facade applications and support the selection of the minimum viable thickness as a design approach. An optimal thickness of 8 mm was determined, providing the optimal balance between translucency (8–4% light transmittance), structural behaviour (flexural strength > 7 MPa) and durability performance (mass losses < 2.34%). Improving the mechanical performance of slender elements by increasing both the contribution of fibres and matrix–waste bonding are among the future follow-up steps. Full article

Aerogel-incorporated foam concrete has attracted significant attention in the construction sector owing to its light weight and superior thermal insulation properties. Nevertheless, its practical application in external wall insulation systems is hindered by the high cost of aerogel (AG) and the inherent trade-off between thermal efficiency and mechanical strength. To overcome these limitations, this study introduces a composite design that partially replaces AG with low-cost hollow glass microspheres (HGMs) and incorporates nano-silica (NS) as a strengthening agent. Foam concrete specimens with a constant dry density of 700 kg/m³ were fabricated with these additives. Through an orthogonal experimental approach, the synergistic effects of AG, HGMs, and NS on mechanical properties, porosity, water absorption, and durability were systematically evaluated. The results demonstrated that 4% AG content significantly reduced effective porosity by 33% and water absorption by 59%, while 4% HGM increased compressive and flexural strength by 13.5% and 19.7%, respectively. The addition of 2% NS further enhanced mechanical performance, yielding 25.9% and 21.6% improvements in compressive and flexural strength. The optimal formulation (A4H4N2) effectively balanced thermal insulation and mechanical properties, offering a viable strategy for producing cost-effective, high-performance foam concrete suitable for building envelope applications. Full article

The global polymer waste burden has catalyzed a shift from linear “production–use–disposal” systems to circular models that prioritize recycling, reuse, and value retention. This article proposes an integrated, technology-ready roadmap for mechanical recycling and reuse of commodity and bio-based polymers via filament re-extrusion and Additive Manufacturing (AM). Building upon recent findings on performance envelopes of virgin vs. recycled Polylactic Acid (PLA) filaments processed by Fused Deposition Modeling (FDM), process parameter sensitivities (layer height, infill density) and their statistical optimization, and functional reinforcement routes (aluminum: Al, alumina: Al₂O₃, titanium: Ti, and Nano Boron Nitride: nano-BN), we articulate (1) a process–structure–property (PSP) mapping; (2) a low-defect, low-energy filament re-extrusion protocol; and (3) a graded-value strategy for upcycling mixed polymer streams. Across case analyses, we show that recycled PLA can achieve near-parity with virgin PLA when extrusion quality and printing parameters are controlled, and that ceramic/metal nanofillers enable thermal management and biocompatibility benefits crucial for durable reuse scenarios. Full article

This study compiles and harmonizes a dataset on the reference service life (RSL) of non-structural building envelope materials in North America. Data was collected from survey-based published reports and Environmental Product Declarations (EPDs) sourced from either manufacturers’ websites or recognized EPD databases. Relevant North American EPDs were reviewed for RSL or equivalent terms, and the extracted RSL values were recorded and classified by material type. The resulting dataset consolidates survey-based service life values, EPD-derived RSLs, together with their reported frequencies, and the extent of missing data. Analysis of the dataset revealed significant data gaps and strong inconsistencies in currently available RSLs. Many published values are based on client surveys or fixed categorical assumptions, overlooking product-specific durability and often relying on data more than 20 years old. These values do not reflect current manufacturing technologies or construction practices. Furthermore, over half of the reviewed EPDs do not report any RSL, while most of the remaining EPDs simply use default values of 60 or 75 years without clear justification. Although the dataset supports sensitivity and uncertainty analyses in building environmental assessments, the findings underscore the lack of reliability and transparency in existing RSL data and highlight the necessity for a consistent and transparent RSL dataset. Full article

Solar absorbers (SAs) are central to building-integrated solar-thermal systems; however, conventional black SAs, despite their high solar absorptance (α_s), offer limited aesthetic flexibility and are therefore poorly suited to modern architectural façades. Brightly colored SAs are widely assumed to suffer from intrinsically low α_s, creating a long-standing trade-off between color vibrancy and energy performance. Here this study reports a dielectric/absorber/dielectric/absorber (D/A/D/A) multilayer architecture, in which the absorber layer is composed of a TiO₂–TiON–C composite, that overcomes this limitation and enables colored solar absorbers (CSAs) with reflectance >20%, α_s > 0.90, wide viewing angles, strong self-cleaning capability, high corrosion resistance and exceptionally long projected service lifetimes. These results demonstrate that vivid coloration and high solar absorptance can be simultaneously achieved without compromising environmental durability. To highlight architectural applicability, we further implement a complementary-color contrast strategy for façade design, yielding visually striking, highly recognizable, and low-cost exterior surfaces. This approach enhances aesthetic integration while significantly strengthening the marketability of CSA-based building envelopes for next-generation sustainable architectural systems. Full article

The thermally efficient and lightweight TRC/CLCi composite panels for functional and smart building envelopes, funded by the iclimabuilt project (Grant Agreement no. 952886), offer innovative solutions to sustainably address common failure risks in facade systems. This work specifically emphasizes strategies for mitigating structural, thermal, and fire-related failures through targeted material selection, advanced design methodologies, and rigorous validation protocols. To effectively mitigate structural failures, high-pressure concrete (HPC) reinforced with carbon fibers is utilized, significantly enhancing tensile strength, reducing susceptibility to cracking, and improving overall durability. To counteract thermal bridging—a critical failure mode compromising energy efficiency and structural integrity—the panels employ specially designed glass-fiber reinforced pins connecting HPC outer layers through the cellular lightweight concrete (CLC) insulation core that has a density of around 70 kg/m³ and a thermal conductivity in the range 35 mW/m∙K comparable to those of expanded polystyrene and Rockwool. These connectors ensure effective load transfer and maintain optimal thermal performance. A central focus of the failure mitigation strategy is robust fire behavior. The developed panels undergo rigorous standardized fire tests, achieving an exceptional reaction to fire classification of A2. This outcome confirms that HPC layers maintain structural stability and integrity even under prolonged fire exposure, effectively preventing catastrophic failures and ensuring occupant safety. In conclusion, this work highlights explicit failure mitigation strategies—reinforced concrete materials for structural stability, specialized glass-fiber connectors to prevent thermal bridging, rigorous fire behavior protocols, and comprehensive thermal performance validation—to produce a facade system that is robust, energy-efficient, fire-safe, and sustainable for modern buildings. Full article

This study systematically evaluates the thermal and humidity control performance of polymer-dispersed liquid crystal (PDLC) smart windows in an operational subtropical commercial building. Conducted from September to November 2025 at the China Railway Construction Building in Zhuhai, China, the field experiment compared four configurations: conventional curtains (fully deployed and fully retracted, respectively) and PDLC film in transparent and opaque states. Results demonstrate that during the high-solar-radiation period (September–October), PDLC in the opaque state exhibited superior thermal control, limiting interior temperature increases to only 2% of the magnitude observed in the transparent state and yielding a maximum interior surface temperature difference of 1.88 °C during peak solar hours (14:00 to 17:00). Humidity fluctuations remained exceptionally stable at ±1.5% in frosted state, significantly outperforming traditional curtain systems (±5.1% to ±8.9%). During November’s transitional climate, the frosted state continued providing thermal buffering, reducing indoor temperature rise by approximately 0.37 °C compared to the transparent state, while the transparent configuration maintained relative humidity approximately 0.5% higher—potentially beneficial for mitigating winter dryness. Cross-seasonal analysis revealed a 57% reduction in indoor temperature rise (from 3.06 °C to 1.31 °C) between September–October and November, directly attributable to seasonal variations in solar geometry. These findings confirm PDLC smart windows’ ability to dynamically regulate temperature, humidity, and daylighting across different seasonal conditions. Despite limitations including non-uniform room geometries and single-climate validation, this research establishes PDLC technology as a promising solution for energy-efficient building envelopes in subtropical regions. Future work should focus on standardized comparative testing, multi-climate validation, long-term durability assessment, and integration with building automation systems. Full article

Soil corrosion is a critical durability and cost factor for metallic foundations in photovoltaic (PV) power plants, yet it is still addressed with fragmented criteria compared with atmospheric corrosion. This paper reviews the main soil corrosivity drivers relevant to PV installations—moisture and aeration dynamics, electrical resistivity, pH and buffer capacity, dissolved ions (notably chlorides and sulfates), microbiological activity, hydro-climatic variability and geological heterogeneity—highlighting their coupled and non-linear effects, such as differential aeration, macrocell formation and corrosion localization. Building on this mechanistic basis, an engineering-oriented methodological roadmap is proposed to translate soil characterization into durability decisions. The approach combines soil corrosivity classification according to DIN 50929-3 and DVGW GW 9, tiered estimation of hot-dip galvanized coating consumption using AASHTO screening, resistivity–pH correlations and ionic penalty factors, and verification against conservative NBS envelopes. When coating life is insufficient, a traceable steel thickness allowance based on DIN bare-steel corrosion rates is introduced to meet the target service life. The framework provides a practical and auditable basis for durability design and risk control of PV foundations in heterogeneous soils. The proposed framework shows that, for soils exceeding AASHTO mild criteria, zinc corrosion rates may increase by a factor of 1.3–1.7 when chloride and sulfate penalties are considered, potentially reducing coating service life by more than 40%. The methodology proposed enables designers to estimate the penalty factors for sulfates ($f_p\left({SO}_4^{2-}\right)$) and chlorides ($f_p\left({Cl}^{-}\right)$) in each specific project, calculating the appropriate values of $K_{{SO}_4^{2-}}$ and $K_{{Cl}^{-}}$ using electrochemical techniques—ER/LPR and EIS—to estimate the effect of the soluble salts content in the ${Zn}_{Corr Rate}$, not properly catch by the proxy indicator $V_{corr}\left(ER, pH\right)$ when sulfate and chloride content are over AAHSTO limits for mildly corrosive soils. Full article

The United Kingdom’s (UK) retrofit revolution is at a crossroads and the efficacy of retrofit interventions is not solely a function of insulation thickness. To truly slash emissions and lift households out of fuel poverty, we must solve the persistent problem of thermal bridging (TB), i.e., the hidden flaws that cause heat to escape, dampness to form, and well-intentioned retrofits to fail. This review moves beyond basic principles to spotlight the emerging tools and transformative strategies to make a difference. We explore the role of advanced modelling techniques, including finite element analysis (FEA), in pinpointing thermal and moisture-related risks, and how emerging materials like vacuum-insulated panels (VIPs) offer high-performance solutions in tight spaces. Crucially, we demonstrate how an integrated fabric-first approach, guided by standards like PAS 2035, is essential to manage moisture, ensure durability, and deliver the comfortable, low-energy homes the UK desperately needs. Therefore, achieving net-zero targets is critically dependent on the systematic upgrade of the building envelope, with the mitigation of TB representing a fundamental prerequisite. The EnerPHit approach applies a rigorous fabric-first methodology to eliminate TB and significantly reduce the building’s overall heat demand. This reduction enables the use of a compact heating system that can be efficiently powered by renewable energy sources, such as solar photovoltaic (PV). Moreover, this review employs a systematic literature synthesis to critically evaluate the integration of TB mitigation within the PAS 2035 framework, identifying key technical interdependencies and research gaps in whole-house retrofit methodology. This article provides a comprehensive review of established FEA modelling methodologies, rather than presenting results from original simulations. Full article