Exterior Cladding Research Articles

Environmental impact of the variations in solar reflectance index values of some selected dimension stones due to cyclic thermal shock

Natural stones are widely used environmentally appropriate building materials as dimension stone both for exterior cladding and floor coverings in urban areas. Depending on their solar reflectivity, these materials may absorb more solar radiation, especially with noontime summer sunlight exposure, which may cause both increasing cooling costs in commercial buildings and overheating of a city with the formation of urban heat islands. Solar reflectance index (SRI) is defined as the ability of a surface to reject solar heat which tends to change with physical, chemical and biological degradation processes by varying solar reflectance (SR) and thermal emissivity (TE) values. Weakening of the stone matrix structure by physical degradation mechanism, such as thermal shock (T-S) cycles mostly have significant impact on SRI. Within the scope of this study, SRI values were calculated before and after cyclic T-S by measuring the optical properties such as SR and TE values of 30 selected sedimentary and metamorphic originated carbonate-based natural stone types. The changes in surface properties such as color, roughness, and gloss, that may have an impact on the SRI values were also analyzed. In addition, a multivariate regression analysis was established to predict SRI value from such properties with a high degree of accuracy. Finally, it was found that, initial SRI values of 9 natural stone types (mostly metamorphic originated) have been increased considerably by cyclic T-S and tend to increase their ability to reduce urban temperatures by higher SRI values, one of the most important selection criteria in energy consumption for natural stones.

Changes in Physical and Water Sorption Characteristics of Three Solid Woods after One-Sided Surface Charring.

One-sided surface charring of wood is a modification process used to lower moisture absorption and improve the resistance to biological degradation for durable surface exterior claddings. Cupressus lusitanica, Gmelina arborea, and Tectona grandis wood samples from fast-growth plantation were charred with a hot plate using three temperatures (300, 350, and 400 °C ± 3 °C) for 10 min. Wood density, surface quality (color and presence of splits), and sorption characteristics (wetting rate and water uptake) were evaluated. Results show that samples charred at 300 °C presented a lower loss of density and thickness than samples charred at 400 °C. Changes in the chemical structure of the wood as a result of the high temperatures caused a decrease of all color parameters (L*, a*, and b*). These values decreased in the samples charred at 400 °C for the three species. Also, the presence of cracks and splits on the surface, or in some cases the presence of detachments from the charring surface, was mostly observed in the samples charred at 350 and 400 °C. One-sided surface charring reduced the liquid water sorption of wood samples in comparison with that of reference samples, especially for C. lusitanica and T. grandis. G. arborea, due to the composition of its anatomical structure and its initial density, chars faster than the other species, causing a greater loss of density, wetting rate values like those of the reference wood, and higher values of water uptake.

Evaluation of exterior wall cavity fires using an intermediate scale test method

AbstractCavities form an integral part of many external wall systems (EWSs). Numerous external wall fires worldwide have been primarily due to combustible exterior cladding. However, the Grenfell Tower and Knowsley Heights fire incidents (in the UK) are examples where wall cavity materials have impacted fire spread. Wall cavity materials are typically regulated by small‐scale fire test methods which do not necessarily represent the actual fire conditions that can exist within wall cavities. This experimental study proposes an intermediate‐scale test (IST) protocol to examine cavity wall fire behaviour. This protocol is a modified version of the FM Global Cavity Fire Test method (within the FM 4411‐2020 series). The study examines a broad range of cavity materials including sarking, polyester insulation, phenolic foam, PIR, and EPS. A low‐intensity (6–8 kW) and high‐intensity (~80 kW) ignition sources were used to represent two types of cavity fire scenarios. These two fire sizes were shown to differentiate reaction to fire behaviour between these materials and explore the “tipping point” in resulting fire behaviour (which may lie between these two intensities). This proposed cavity fire test protocol provides a suitable “elevated fire risk assessment tool” for combustible cavity materials.

Effect of climate and wood type on elastic modulus of heat-treated wood and its optimization by the Taguchi method

Wood, as the oldest building material, provides some of the basic needs of human beings, including shelter and protection. Wood is used in exterior cladding, carrier systems, joinery, ceiling-floor coverings, windows, doors, and furniture production. When wooden material is exposed to external weather conditions, due to its hygroscopic structure, its physical and mechanical properties deteriorate from exposure to moisture, temperature, and biological organisms. The bending modulus of elasticity of Scots pine (Pinus sylvestris L.), oak (Quercus petraea L.), and chestnut (Castanea sativa M.) wood that was tannin-impregnated and heat-treated at 160 °C, was investigated using Taguchi L9 (33). The sequence was optimized. After heat treatment, the carrier elements were subjected to artificial climate conditions. In the optimization of the data obtained, it was understood that the highest impact factor was the tree type. In contrast, the climate on the elastic modulus was the lowest impact factor. In Taguchi analysis, a mathematical prediction model was created using actual and predicted data using the S/N ratio’s biggest-best equation. The R2 of the model can be predicted with an accuracy rate of 98.6%.

Exterior cladding in the German architecture of Valdivia. A metaphor of refinement and social distinction

As a result of the colonization process that began in the mid-19th century in southern Chile and, with it, the systematic arrival of European immigrants, an informal discourse has been favored over time to sustain the transcendent contribution of foreigners in the area, as well as the architectures accrued, thus emerging a widely spread valuation and cataloging discourse; the «German architecture of southern Chile.» Notwithstanding the widely publicized colonizing agenda and its overall impact, economic progress and better material conditions are not transversal issues within this migrant colony. Within this scenario, the Typical Zone of General Pedro Lagos Street, located in the city of Valdivia, constitutes a highly representative sector in terms of its social recognition and the valuation given to the properties located there as exponents of a prolific colonization process. In a specific group of buildings in this area, this article will review and present detailed background information that will allow building a situated and complex architectural scene, revealing the mechanisms used to exhibit prosperity and social climbing as an expiatory vehicle to cover production conditions alien to the neatness of capitalist German entrepreneurship and the European sophistication that was so desired to be transmitted in the cities undergoing fledgling immigration processes.

Innovative PCM-incorporated foamed concrete panels for walls’ exterior cladding: An experimental assessment in real-weather conditions

This study aims to develop innovative exterior cladding panels capable of improving the walls’ thermal performance for new and existing buildings. A phase change material (PCM) was incorporated into foamed concrete (FC) to develop innovative PCM-incorporated FC (PCM-FC) cladding panels, which were assessed as an exterior finishing of cement brick wall and compared to the conventional cement rendering. The test was conducted using reduced-scale testing cells in real-weather conditions and for four cardinal orientations. The developed PCM-FC cladding panels yielded remarkable reductions in the wall’s internal surface temperature and the cell’s internal air temperature, reaching 6.75 ℃ and 5.50 ℃, respectively. Moreover, the developed cladding panels performed effectively for the four cardinal orientations, yet their effectiveness varied according to the intensity and the time of receiving direct solar radiation. Furthermore, a low decrement factor of 0.49 and a 32.1% reduction in the intensity of overheating were obtained when using PCM-FC cladding panels compared to Ref-CR. The developed PCM-FC cladding panels substantiated superior thermal performance in reducing external heat gain, which results from the combined effects of PCMs’ high thermal energy storage and FC’s low thermal conductivity. Therefore, these PCM-FC cladding panels can potentially contribute to reducing buildings’ high energy consumption.

Effect of Expanded Perlite Aggregate Plaster on the Behavior of High-Temperature Reinforced Concrete Structures

Polyurethane-based materials, which are widely used in exterior cladding, pose a great risk for buildings because they can easily catch fire at temperatures as low as 50–65 °C. Thus, different materials are needed to ensure that structures exposed to high temperatures do not have any stability problems. In this study, expanded perlite aggregate plaster (EPAP) was produced to eliminate the negative effects that may occur in buildings exposed to high temperatures. High temperature tests were carried out on test plates of different thicknesses to determine the effect of plaster thickness under high temperatures. In order to compare the effects of high temperatures, a test sample of normal aggregate plaster (NAP), which is widely used in buildings, was prepared. In the high temperature test, the temperature values on the back surfaces of the EPAP (≈115 °C) test plates were approximately 3 times lower than the temperature values of the NAP (≈350 °C) test plate. It can be said that structural stability loss and durability problems may occur in structures covered with NAP in a high-temperature environment, and that no negative effect will occur in terms of structural stability and durability problems in structures covered with EPAP in high temperature environments.

Design and optimization of carbon fiber eight-wire lifter with exterior cladding structure

The UHV eight-wire lifter is an important tool in frequent use for the construction and maintenance of UHV transmission lines, which is made of titanium alloy and weighs about 40 kg. Due to high-weight, the work efficiency is greatly reduced. In this paper, the design of a lightweight UHV eight-wire lifter is proposed by using carbon fiber cladding structure. The effects of three factors on the maximum load-bearing load of the carbon fiber exterior cladding structural member are excavated through the failed experiment of the carbon fiber exterior cladding tensile and shear test pieces and the finite element progressive damage numerical calculation. The orthogonal experiment is employed to obtain the optimal cladding structure of the eight-wire lifter with a carbon fiber exterior coating cladding. After that, carbon fiber eight-wire lifter is developed and subjected to mechanical tests. The test results show that the performance of carbon fiber eight-wire lifter meets the mechanical performance requirements of eight-wire lifter. Compared with the titanium alloy eight-wire lifter, the maximum load-bearing load of the carbon fiber eight-wire lifter is increased by 20.5%, and the weight is decreased by 37.5%.

Experimental procedure for studying the degradation and alteration of limestone slabs applied on exterior cladding

The studied limestone is a well known Portuguese natural stone that occurs in Valverde—Alcanede region, located in the Maciço Calcário Estremenho (center of Portugal). This stone is used in several exterior and interior applications such as paving, cladding, masonry and decorations. Slabs made of the studied limestone were installed in ventilated facade with a “kerf” anchoring system in a building located in Valencia (Spain). After approximately five years, signs of degradation were detected on the facades through changes in color, enhancment of cracks and fissures that caused instability and collapse on several slabs. Limestone slabs comprise irregular patterns due to rock cutting across stylolites. These features represent ideal paths for fluid circulation through the slab and can be identified as vulnerability zones for exterior applications. Experimental procedure included several laboratory analyses to study clays and the iron oxide contents. Microscopic petrography, XRD and SEM observations were important to identify the interaction of the clay material in stylolites and fossil contours. Results show the importance of establishing standard methods for selecting stone on cladding applications. From the results, it is possible to understand that clay minerals have a strong influence on the mechanical performance of this stone. Among other important remarks, results show the importance of the development of standard procedures that acknowledge the structure and mineral composition before setting these natural products as construction materials. Proper stone selection was found important to avoid facade degradation, and hence contribute to prevent accidents and promote user safety as well as economic impacts.

NOWE ROZWIĄZANIA TECHNICZNE W DOSTOSOWANIU ZABYTKU DO STANDARDU BUDYNKU NIEMAL ZEROENERGETYCZNEGO NA PRZYKŁADZIE KAMIENICY W POZNANIU

This article aims at discussing the issue of relation between an existing historic building and modern technology, which may lead to upgrading the historic building to parameters of a nearly zeroenergy building. It focuses on the possibility to adjust the facility to contemporary forms of using without considerable prejudice to its historic substance and identity, on contrary, with due respect for the old tissue in the context of NZEB parametrisation. The adjustment refers to innovative solutions allowing upgrade of the building by using the most effective technologies based on renewable energy, improved power efficiency of the structure, technical equipment, exterior and interior cladding and meeting requirements connected with minimum global cost in the life cycle assessment of the building.

A study on Carbon Fiber Based Polymer Rein Force composites

Functional compounds are materials with mechanical integrity, whose functional properties can be achieved, enhanced orenhanced by a combination of two or more components. ... Non-functional carbon material and two- and three-dimensional materials. Energy conversion and storage materials and structures. Compounds are generally characterized compounds (CAMCs). Polymer Matrix - Polymer matrix compounds (PMC) can be divided into three subtypes: thermoses, thermoplastic and rubber. A polymer is a large molecule formed by repeating structural units bonded by covalent chemical bonds. Structural compounds are engraved products made of plastic, wood, glass or carbon fiber materials. Developed or extruded products have applications such as exterior floors, rails, fences, natural wood, cladding, sidewall, molding, trim and window or door frames. Structural compounds are engraved products made of plastic, wood, glass or carbon fiber materials. Developed or extruded products have applications such as exterior floors, rails, and fences, natural wood, cladding, sidewall, molding, trim and window or door frames. A particle is not a long dimension. Particle compounds the particles of one substance are scattered in the the second object team. Particles can have any shape and size, but generally spherical, a particle composite is classified as a group of suspended particles. Particles can have any shape, size or structure. Examples of well-known particle composites are concrete and particle board.

TiO2-based glass-ceramic coatings: An innovative approach to architectural panel applications

Exterior claddings are used for architectural purposes primarily for practical and esthetic reasons. Panels are subjected to a variety of impacts, including chemical, and ultraviolet radiation, and are intended to survive them. In this study, the color, gloss, chemical and UV resistance, impact resistance, and surface tension of glass-ceramic (GC) coated steel panels and other products on the market, such as conventional ceramic wall tiles, glass, and aluminum panels, are compared. Three different types of GC powders were prepared: opaque, semi-transparent, and transparent. Each GC powder was applied to a pre-coated steel substrate. Chemical resistance was excellent in all samples, however, only the GC-coated steel panels and the aluminum panels satisfied the impact resistance criteria. A UV test was performed to ensure that surface characteristics such as gloss, color, and surface tension were stable in the presence of UV light. The aluminum gives alerts the most color shift (∆E ≈ 1.2), whereas the GC-coated steel panels showed just ∆E ≈ 0.2. The gloss values of the samples did not change significantly much. Furthermore, when compared to the other products, GC-coated samples had the lowest weight and the greatest performance.

Sensitivity analysis of hygrothermal performance of wood framed wall assembly under different climatic conditions: the impact of cladding properties

One of the parameters that influences the moisture performance of the wood framed wall assembly is the material properties of exterior cladding. The uncertainties of its properties, would result in a range of wall performance. The objective of this study was to investigate the impact of uncertainties in cladding material properties on moisture performance of wood framed wall assembly under different climatic conditions. A wood framed (2×6 wood stud) wall with exterior brick cladding was simulated assuming 1% rain leakage deposited on the exterior side of sheathing membrane. A parametric study was carried out to analyze the impact of the cladding properties on the moisture response of OSB. The simulations were conducted in five different cities located in different climate zones across Canada. The aim was to identify the most influential cladding property on the moisture response of OSB, i.e., mould growth index and moisture content, to the varying cladding properties under different climatic conditions i.e., different cities under historical and future conditions. In general, it was found that liquid diffusivity is the parameter that has the most influence on moisture response of OSB in all the five cities. Also, the significance of this influence varies depending on the climatic conditions.

Durability and Fire Performance of Charred Wood Siding (Shou Sugi Ban)

Shou sugi ban, also known as yakisugi, or just sugi ban, is an aesthetic wood surface treatment that involves charring the surface of dimensional lumber, such as exterior cladding. The goal of this research is to examine the effect of shou sugi ban on the flammability and decay resistance of wood. Several species and variants of commercially available sugi ban were tested. The flammability was examined from the heat release rate curves using the oxygen consumption method and cone calorimeter. Durability was examined with a soil block assay for one white-rot fungus and one brown-rot fungus. The testing showed that the shou sugi ban process did not systematically improve the flammability or durability of the siding.

Experimental investigations on the influence of ‘chimney-effect’ on fire response of rainscreen façades in high-rise buildings

In recent years, external wall fires (or façade fires) are occurring due to mixed contribution of exterior cladding and continuous insulation in the chimney like construction of rainscreen façades. In the present work, a new experimental setup is developed and demonstrated for the initial screening of façade assembly at a lab-scale. It incorporates the real physics for investigating the fire hazards of flammable polymeric materials and the chimney effect together. Different combinations of exterior cladding (Al-45, Al-45 Class 0, Al-45 Class B) and continuous insulation (Expanded polystyrene, Polyisocyanurate and Mineral wool) with and without chimney are selected for studying their fire behaviour. The pressure differential combining with re-radiation inside the cavity led 3–6 times higher mass burning rate, flame height and temperature in tests with chimney effect to that of without for the same combination of products. With chimney, secondary fire sources are generated due to the dripping of products which further enhanced the burning and spread rate. A critical width of the chimney (13–50 mm) is established at which maximum vertical fire spread was noticed. Furthermore, the visual observations indicated that the products having thin outer Al sheets are prone to 30% early structural failure. Comparison of results with large-scale tests validated the usefulness of the current setup as an intermediate test between small and large scale for studying fire behaviour of façade materials.

Hardness and contact angle of thermo-treated poplar plywood for bio-building

Abstract: The interest towards poplar cultivation and its wood has recently been growing in Italy, where the use of timber and wood-based materials in construction is increasing as well. Poplar plywood, with a national production of around 270.000 m3 in 2017, is a key product for the Italian wood sector, and currently is destined for several applications as component for furniture and motorhomes. Previous research has shown that thermal treatment can be effectively applied to poplar plywood in order to make it suitable to the requirements of new end-uses. The present study aims to widen the knowledge of the effects of thermal treatment on poplar plywood. With this purpose, 7-layered, 12-mm thick plywood bonded with urea-melamine-formaldehyde (UMF) resin was thermally treated for 2 h at 170, 190 and 210 °C through the Termovuoto® process. The treatment aimed to improve the dimensional stability and durability against fungal decay. The process was set at lower temperature and shorter time than those of many thermal treatments commonly used in practice in order to limit the reduction in mechanical properties and to maintain an adequate bonding quality. The above properties were already verified by previous research, whereas in this study Brinell hardness and contact angle of treated panels were investigated as relevant for several end-uses that can be prospected in building and in outdoor environments. Brinell hardness decreased from 10.8 to 8.3 N mm-2 and contact angle increased from 75.8° to 103.6°. Overall, treatment at 190 °C seems the most suitable to induce balanced modifications in the panels. From a technical point of view, these appear ready to enter the market, for instance for use in exterior claddings, partitions and outdoor flooring.

Hygrothermal performance, energy use and embodied emissions in straw bale buildings

Straw bale is a low embodied energy and technically acceptable thermal insulation material. As per today, there is a lack of standardized technical data on utilizing straw bale in building construction, while the existing research studies rather focus on limited specific experimental or computational scenarios without summarizing in an organized way the behaviour of straw bale construction under different climate conditions and assembly configurations. This comparative study presents systematically the hygrothermal and energy performance of straw bale buildings with different exterior cladding and finishing mortar or sheathing board, exposed in various representative climates. The findings provide an insight into the optimal selection of materials and furthermore highlight the importance of climate adaptation of straw bale wall constructions. Overall, straw bale buildings show robust hygrothermal performance, when properly designed, and achieve very low energy use at a minimum of embodied emissions.

Characterization of travertine stones from Turkey and assessment of their durability to salt crystallization

The travertine is used in the construction industry for ornamental purposes such as exterior and interior cladding and floor tiles. Travertine, which is a carbonate-stone, deteriorations over time like other porous building stones. Salt crystallization is one of the main reasons for the degradation of building stones. Therefore, examples of three types of travertine from Turkey and commonly recognized worldwide were tested for salt crystallization resistance. The travertine samples tested were subjected to aging tests through salt crystallization (sodium sulfate and sodium chloride) cycles to simulate the deterioration phenomena. In terms of support for these studies, first, the petrophysical properties of travertine were determined. Travertine samples were characterized by mineralogical-petrographic (optical microscope, SEM), chemical (XRF), and mechanical-physical tests. After the aging process, changes in some petrophysical properties of the tested travertine were studied. Changes in the tested travertine structure after these aging tests were determined using SEM, uniaxial compressive tests, and ultrasonic wave measurements. According to results after the salt crystallization tests, all tested travertine had a dry weight loss of less than 1.0%. All travertine samples showed a reduction in the compressive strength and ultrasonic velocity after the crystallization tests. The uniaxial compressive strength values after salt crystallization tests of Denizli, Emirdağ, and Kütahya travertine samples indicate a decrease of about 59.83, 88.43, and 44.23% on sodium sulfate, and 34.30, 44.23, and 24.85% on sodium chloride solution, respectively. After sodium sulfate and sodium chloride test in Denizli, Emirdağ, and Kütahya travertine, ultrasonic velocity values decreased by 59.94, 54.32, 68.63%, and 49.60, 46.79, 61.83%, respectively.

Watertightness performance of face-sealed versus drained window-wall interfaces

Several research studies have identified window-wall interfaces as one of the major sources of water ingress through building envelopes. Window-wall interfaces can either be sealed by means of face-sealed or drained sealing systems. In general, it is assumed that drained window-wall interfaces show an improved rainwater resistance compared to face-sealed interfaces. However, only a limited number of studies can be found in literature evaluating the watertightness performance of both face-sealed and drained window-wall interfaces. The objective of this paper is to evaluate the performance of both face-sealed and drained sealing methods and to identify the primary factors affecting the water resistance of window-wall interfaces.Various combinations of exterior seal, drainage layer, air barrier, airtightness level, installation method and wall assemblies were assessed by means of 5 face-sealed test specimens and 9 drained specimens. Both static and cyclic tests were performed. It was found that both tests showed corresponding results with regard to the pressure threshold value for water ingress. The results in this study also indicated that the airtightness of the interfaces and the presence of a separate air barrier at the interior side of the interface affected the watertightness performance to a great extent. The findings showed that it is very difficult to obtain water resistant face-sealed window-wall interfaces, even in lab conditions. It is therefore recommended to always provide drainage possibilities behind the exterior seal or cladding.

Experimental investigation of an innovative composite mullion made of aluminium and timber

The façade, as the exterior cladding of a building, is an essential element which provides waterproofing, thermal isolation and structural resistance against environmental actions. The vertical members in curtain wall façade systems, referred to as mullions, are the dominant load-bearing structural members. Despite aluminium being a durable material, conventional aluminium façade frames are weak in thermal performance, and hence thermal breaks are often used in the industry to provide the required insulation. In addition, timber frames may be preferred by building designers due to their aesthetic appearance and sustainability. Therefore, an innovative composite mullion was developed using aluminium and timber to combine the best features of both materials and is presented in this study. Experimental studies were also conducted to verify the structural performance of the composite mullion. The first series of tests was performed to investigate various aluminium-timber connections to ensure composite action. Four different connection types were considered in this study and the optimum connection was chosen and discussed. Four-point bending tests were performed next to investigate the bending behaviour and strength of the newly developed mullion as well as traditional aluminium mullions under positive and negative wind loading scenarios. It was found that the new composite mullions achieved higher section moment capacities than the traditional aluminium mullions, while being energy-efficient, aesthetically pleasing and more sustainable.