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The rationale for this work arose from the urgency of improving the energy efficiency of buildings at the design stage, given the changing requirements of energy efficiency standards such as the Polish Technical Conditions (WT 2014 and WT 2020). This research is novel as there is currently limited information available on the improvement of the thermal performance of ventilated stone facade systems, although they are now widely used due to their practical and aesthetic advantages. The first objective of this work is to evaluate the thermal performance of the ventilated facades of the Praski Student House (Akademik Praski) and to assess how certain design variations can help achieve a lower level of energy consumption. Using a comprehensive case study approach, this study provides accurate thermal calculations of the facade to assess its global thermal insulation coefficient (Rt) and thermal transmittance (Uc). The improvement in the actual U-value from the original design is as follows: the U-value is reduced from 0.33 originally to 0.228 for WT 2014 and to 0.198 for WT 2020, showing a reduction of about 30.9% and 13.2%, respectively. These results indicate the energy efficiency of increased insulation thickness and optimally oriented air gap dimensions. The practical contributions of this research are valuable for architects, engineers, and contractors involved in the design and construction process of buildings aiming to achieve near-zero energy buildings (nZEBs), including concrete suggestions on how to improve current construction practices as well as material recommendations. There is a need for durability studies, for example to assess the performance of such facades under different climatic conditions, as part of future work to support these findings. [ABSTRACT FROM AUTHOR]

The rationale for this work arose from the urgency of improving the energy efficiency of buildings at the design stage, given the changing requirements of energy efficiency standards such as the Polish Technical Conditions (WT 2014 and WT 2020). This research is novel as there is currently limited information available on the improvement of the thermal performance of ventilated stone facade systems, although they are now widely used due to their practical and aesthetic advantages. The first objective of this work is to evaluate the thermal performance of the ventilated facades of the Praski Student House (Akademik Praski) and to assess how certain design variations can help achieve a lower level of energy consumption. Using a comprehensive case study approach, this study provides accurate thermal calculations of the facade to assess its global thermal insulation coefficient (Rt) and thermal transmittance (Uc). The improvement in the actual U-value from the original design is as follows: the U-value is reduced from 0.33 originally to 0.228 for WT 2014 and to 0.198 for WT 2020, showing a reduction of about 30.9% and 13.2%, respectively. These results indicate the energy efficiency of increased insulation thickness and optimally oriented air gap dimensions. The practical contributions of this research are valuable for architects, engineers, and contractors involved in the design and construction process of buildings aiming to achieve near-zero energy buildings (nZEBs), including concrete suggestions on how to improve current construction practices as well as material recommendations. There is a need for durability studies, for example to assess the performance of such facades under different climatic conditions, as part of future work to support these findings.

The evaluation of the shear performance of stone panel–panel joints (SPPJs) in stone cladding has important engineering significance, as it plays a crucial role in stone cladding failure. The purpose of this paper is to analyze and predict the influence of the dimension and the Young's modulus of sealant on the shear performance of SPPJs. Based on monotonic and cyclic loading tests, the effects of Young's modulus and the dimension of sealant on the failure characteristics, stress–strain characteristics, stiffness degradation, and energy dissipation capacity of an SPPJs were investigated. According to finite element analysis, the strain distribution of an SPPJ under monotonic loading was analyzed for different sealant widths and number of sealant layers. The results indicate that the failure modes of SPPJs change with the variation of sealant amount. As the Young's modulus of the sealant increases, the shear failure strength and shear yield strain of SPPJs increase. The increase in sealant thickness reduces the shear failure strength and stiffness of SPPJs. Based on the same shear strain, the increase in the sealant thickness enhances the cumulative energy consumption of SPPJs. The strain concentration zone of the specimens with two sealant layers in unilateral SPPJs becomes larger with the increase in sealant width. [ABSTRACT FROM AUTHOR]

The evaluation of the shear performance of stone panel–panel joints (SPPJs) in stone cladding has important engineering significance, as it plays a crucial role in stone cladding failure. The purpose of this paper is to analyze and predict the influence of the dimension and the Young’s modulus of sealant on the shear performance of SPPJs. Based on monotonic and cyclic loading tests, the effects of Young’s modulus and the dimension of sealant on the failure characteristics, stress–strain characteristics, stiffness degradation, and energy dissipation capacity of an SPPJs were investigated. According to finite element analysis, the strain distribution of an SPPJ under monotonic loading was analyzed for different sealant widths and number of sealant layers. The results indicate that the failure modes of SPPJs change with the variation of sealant amount. As the Young’s modulus of the sealant increases, the shear failure strength and shear yield strain of SPPJs increase. The increase in sealant thickness reduces the shear failure strength and stiffness of SPPJs. Based on the same shear strain, the increase in the sealant thickness enhances the cumulative energy consumption of SPPJs. The strain concentration zone of the specimens with two sealant layers in unilateral SPPJs becomes larger with the increase in sealant width.

Starting from the analysis of the archival and bibliographical documentation and from the direct observation of the buildings, the article analyses the finishing surfaces of the residential buildings designed by Giuseppe Terragni, in order to understand the structural and technological construction choices, the results on site and the changes that such finishes have undergone over time. From 1927 and 1943, Giuseppe Terragni designed and built, alone or in cooperation with other architects (Pietro Lingeri e Alberto Sartoris), nine buildings intended for multi-family dwellings and two single-family villas. For the outer finishes of his architecture works, he experimented different solutions: plaster finishes, stone cladding in large slabs and smaller elements, as well as cladding with prefabricated elements of cement grit. Despite Terragni’s declare wish to create durable finishes which could withstand the effects of the weather, most have undergone modifications and transformations. Le superfici esterne negli edifici residenziali progettati da Giuseppe Terragni. Intonaci, rivestimenti in pietra e elementi prefabbricati alla prova del tempo L’articolo, partendo dall’analisi della documentazione archivistica, bibliografica e dall’osservazione diretta degli edifici, analizza le superfici di finitura degli edifici residenziali progettati da Giuseppe Terragni per comprenderne le scelte formali e tecnologico costruttive, gli esiti in cantiere e le modifiche che tali finiture hanno subito nel tempo. Giuseppe Terragni, dal 1927 al 1943, ha progettato e realizzato, da solo o in collaborazione con altri architetti (Pietro Lingeri e Alberto Sartoris), nove edifici destinati ad abitazioni plurifamiliari e due ville monofamiliari. Per le finiture esterne delle sue architetture sperimenta diverse soluzioni: finiture ad intonaco, rivestimenti lapidei in lastre di grandi dimensioni e in elementi più piccoli oltre a un rivestimento in elementi prefabbricati in graniglia di cemento. Nonostante la dichiarata volontà di Terragni di realizzare finiture durevoli, che potessero resistere all’azione degli agenti atmosferici, la maggior parte hanno subito modifiche e trasformazioni.

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The successful quality management of the external stone cladding system in production and installation stages is of vital importance to ensure the high quality of the completed system. Nevertheless, little research has been conducted in this area. This research aimed to report the current status of the external stone cladding system in the production and installation stages in Hong Kong. To do so, this paper examines its current practices and major issues occurred through case studies, questionnaire surveys, and interviews. The results revealed the insufficiency in control mechanism and quality control in the system in Hong Kong. Furthermore, the factors to ensure the quality of the two stages were determined. Lastly, this research suggested recommendations on the possible measures to improve the system quality: pre-testing of stone materials and anchorage system, quality assurance of suppliers and manufacturers, regular inspections and audits on production, and continuous site quality supervision and checklist. The findings and outcomes of the research could lead to actions to guarantee steady quality for the stone cladding façade. [ABSTRACT FROM AUTHOR]

The successful quality management of the external stone cladding system in production and installation stages is of vital importance to ensure the high quality of the completed system. Nevertheless, little research has been conducted in this area. This research aimed to report the current status of the external stone cladding system in the production and installation stages in Hong Kong. To do so, this paper examines its current practices and major issues occurred through case studies, questionnaire surveys, and interviews. The results revealed the insufficiency in control mechanism and quality control in the system in Hong Kong. Furthermore, the factors to ensure the quality of the two stages were determined. Lastly, this research suggested recommendations on the possible measures to improve the system quality: pre-testing of stone materials and anchorage system, quality assurance of suppliers and manufacturers, regular inspections and audits on production, and continuous site quality supervision and checklist. The findings and outcomes of the research could lead to actions to guarantee steady quality for the stone cladding façade.

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, the combination of bowing with wind pressure effects on the building façades can increase the risk of fracture and collapse of the stone slabs, especially if this combination is not properly evaluated during design. Motivated by a case study, this work describes a stability evaluation of a 15-year-old building façade coated with marble stone cladding affected by bowing and subjected to wind pressures. This evaluation was focused on the stone slabs, and was performed through finite element model (FEM) numerical simulations of these slabs submitted to wind pressures and through lab tests using samples of stone slabs removed from the building façade. The results obtained demonstrated stability problems on the stone slabs caused by wind pressure-induced stresses combined with the loss of strength due to aging and bowing effects, especially for slabs with larger dimensions.

This paper intends to establish a model for the service life prediction of natural stone claddings with indirect fastening system based on a survey of the degradation state of 142 buildings in the Lisbon area. The state of degradation is evaluated through visual inspections that allow describing the extent of the cladding area affected by the different anomalies, thereby enabling the level of severity of the anomalies detected to be established. A numerical index of the degradation severity of stone claddings (Sw) is established; this is intended to express the global degradation level of these claddings, thus allowing the study of the evolution of their degradation with time to estimate a reference service life of this type of cladding. The results achieved in this study allow analyzing the influence of some intrinsic and extrinsic characteristics on the durability and service life of natural stone claddings with indirect fastening system. The information provided by the proposed models is essential for the definition of maintenance strategies, promoting a rational and sustainable management of the built heritage, optimizing the use of resources, and minimizing the overall cost of the building over its lifecycle. [ABSTRACT FROM AUTHOR]

Stone roof coverings have existed for hundreds of years now, but their application in contemporary representative architecture is quite different than it was in former times, and accordingly the underlying constructional details are much more complicated. The main role of the roof in today's architecture is to emphasize the abstract building volume and its homogeneity. The design (visual appearance) has priority over constructional considerations, while at the same time requirements for thermal insulation and the watertight buildup of the building envelope are rising. This is a big challenge for the design of the constructional details, since traditional methods do not apply anymore: almost all of the water gets under this exterior cladding where a completely waterproof underlayer is needed. Therefore a new type of constructions is borne. In this article I try to present innovative constructional alternatives for stone cladded roofs and try to define guidelines for their planning. These alternatives were created and refined based on analysis of historical and contemporary examples, the examination of the specific conditions and requirements that affect cladded roofs, their expected performance over their life-span, the difficulties that arise under construction and my work experience. I created seven groups, according to the method for fixing the individual stone elements, since this is the detail that most affects the buildup of the underlying structure. A new approach is needed with these unconventional constructions, with a much more detailed inventory of every little feature of the building in question. But since these features vary violently with the architectural conception the exact constructional solutions are usually unique as well.

During their lifecycle, a building and its components should fulfill a set of performance requirements. However, in reality, from the moment in which a building is placed in use, its deterioration process begins. Buildings and especially their façades, more exposed to the external environmental agents, suffer throughout their service life several types of depreciation, becoming obsolete, economically destitute, or physically deteriorated, leading to the end of their service life. This paper intends to establish a correlation between functional criteria (FBSL) and physical degradation (Sw) in the definition of service-life prediction models. In this study, these models are applied to 203 natural stone claddings (directly adhered to the substrate), located in the Lisbon area, Portugal. The functionality and degradation condition of the façades analyzed are evaluated through visual inspections. Vulnerability and risks (intrinsic and extrinsic variables) are considered in the evaluation of both methods, as the factors that affect the physical and functional service life of buildings. These models are implemented based on a survey of expert opinion. This study allows establishment of a hierarchical scale concerning the priority of intervention in the stone claddings, based on physical and functional criteria. This information is extremely important in the implementation of maintenance programs in large building stocks. [ABSTRACT FROM AUTHOR]

A method capable of characterizing artificial weathering damage in dimension stone cladding using access to one side only is presented. Dolomitic limestone test samples with increasing levels of damage were created artificially by exposing undamaged samples to increasing temperature levels of 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, and 700°C for a 90 min period of time. Using access to one side only, these test samples were nondestructively evaluated using a nonlinear approach based upon noncollinear wave mixing, which involves mixing two critically refracted dilatational ultrasonic waves. Criteria were used to assure that the detected scattered wave originated via wave interaction in the limestone and not from nonlinearities in the testing equipment. Bending tests were used to evaluate the flexure strength of beam samples extracted from the artificially weathered samples. It was observed that the percentage of strength reduction is linearly correlated (R² = 98) with the temperature to which the specimens were exposed; it was noted that samples exposed to 400°C and 600°C had a strength reduction of 60% and 90%, respectively. It was also observed that results from the noncollinear wave mixing approach correlated well (R² = 0.98) with the destructively obtained percentage of strength reduction. [ABSTRACT FROM AUTHOR]

The last few years have seen expressions of concern about the sustainability of construction from all actors in the sector. The durability of the materials used has, in particular, been mentioned as a determining factor in increasing the service life of structures and consequently in reducing energy consumption and environmental impacts as a whole. With the introduction of new products and/or the adoption of new constructive techniques it has become necessary to develop the fields of durability and service life prediction of construction products, with the purpose of evaluating their performance throughout their life cycle. A model to estimate the service life of natural stone claddings is put forward, based on the factor method initially proposed by the Architectural Institute of Japan. This method involves the appraisal of the degradation phenomena in stone claddings under real use conditions, through a field survey. 269 stone claddings located in Portugal were analysed. The factors that affect the durability of natural stone claddings were examined. The quantification of the factors affecting the durability of stone claddings is affected by some subjectivity. Therefore it does not seem viable to propose standard values that can be applied in all circumstances. Analysis of the scenarios proposed for that quantification shows that the use of generic values for durability factors, such as those in ISO 15686:2000, does not lead to the best results. The best solution is to adopt durability factors adjusted to the reality of the phenomenon to be modelled at a regional or local scale. This is a first approach to applying the factor method to estimate the service life of natural stone cladding. It is considered that the method proposed shows very promising results, though it still needs to be supplemented, particularly in terms of the comprehensiveness of the sample. [ABSTRACT FROM AUTHOR]

Highlights: [•] This article enhances granite behaviour to high temperature. [•] Changes in physical and mechanical properties due to thermal exposure. [•] Implications on granite cladding dimension requirements are highlighted. [Copyright &y& Elsevier]

Purpose – The purpose of this paper is to present a systematic approach for the evaluation and selection of curtain wall systems for medium-high rise building construction. Design/methodology/approach – The authors have identified the different types of curtain wall systems that are commonly used in the building construction industry in Saudi Arabia; examined the various performance as well as financial and non-financial criteria affecting the evaluation and selection of these systems; and subjected the identified different types of curtain wall systems to several filtering processes, namely feasibility ranking, evaluation by comparison and weighted evaluation to facilitate making a decision on the most suitable system to select. Findings – The analysis of the collected data indicated that the precast concrete curtain wall system is considered to be the first choice. The second choice is the prefabricated brick panel curtain wall system. Originality/value – Curtain walls are the most recognized elements of contemporary structures today. There exists ample variety of materials and designs that could be utilized for the development of these building elements. This paper is of practical value to project owners, architects and design professionals endeavoring on the process of selecting and specifying curtain wall systems in their projects. [ABSTRACT FROM AUTHOR]

Abstract: The mechanical behaviour of transventilated façades performed by natural stone is necessarily based on the correct execution of both anchoring elements on the stone cladding as in the ones corresponding to the enclosure support, either with brick masonry walls or reinforced concrete walls. In the case studied in the present work, the origin of the damages suffered on the façade of a building located in Alcoy has been analyzed, where the detachment of part of the outer enclosure occurred. This enclosure is a transventilated façade formed by Bateig Blue stone tiles. To this end, “in situ” tests of the anchoring systems employed have been performed, as well as laboratory tests of mechanical characterization of the material and of different types of anchor, comparing these results with those obtained in both the simplified analytical models of continuum mechanics as developed by the Finite Element Method (FEM). [Copyright &y& Elsevier]

Environmental factors directly affect a building's performance and durability. They are particularly detrimental in the case of building envelope materials and systems because these tend to exhibit a large exposed area and relatively narrow thickness. Therefore, tools are needed to model degradation and provide an insight into its occurrence and its relationship with the environmental factors that have the worst effect. In this paper, the degradation of stone wall cladding directly adhered to the substrate is estimated based on the evaluation of the characteristics of 140 wall cladding systems inspected in Lisbon, Portugal. Because it is a complex phenomenon, a probabilistic analysis is developed using multinomial logistic regression. The analysis focuses on the environmental factors that most influence the overall degradation of the façades (condition level). Probabilistic patterns are thus obtained for the evolution over time of each condition level according to their exposure level to outdoor environmental conditions. [ABSTRACT FROM AUTHOR]

Abstract: The paper reports the results of a multi-disciplinary study carried out on a significant example of Modernist architecture, dating back to the Fascist period in Italy. The buildings of that period are as laboratories for architectural innovation and are characterized by the adoption of new constructive and technological solutions for the elimination of the decorative and functional element in order to obtain pure volumes. This characteristic feature caused in a great number of Modern buildings design errors and the deterioration of the unprotected elements. In order to safeguard this heritage it is necessary to have a thorough understanding of the materials and the techniques used. This can be achieved only through a multi-disciplinary approach on relevant case studies. The current study was carried out on the characteristic construction components of the main façade of a selected building, the stone cladding and the steel windows, to have a more thorough awareness of the techniques used and to verify the state of conservation. It was also possible to hypothesise conservation actions coherent with the material culture. [Copyright &y& Elsevier]

Abstract: Based on a proposal for a classification system for anomalies and their probable causes in natural stone cladding (NSC) an inspection plan was developed for recent buildings with anomalies in this type of cladding, to validate the system. This field work generated data from 59 buildings whose cladding exhibited various anomalies, in a grand total of 288. A specific area of Lisbon city (Portugal) was selected for most of the inspections: The Parque das Nações – an urban area that was regenerated for the Expo’98 World’s Fair. Based on these inspections, a comparative analysis was performed on various surfaces clad in this material, i.e. pavements versus walls and indoor versus outdoor applications. The resulting data underwent a statistical analysis and post-treatment, providing conclusions that could lead to actions to prevent degradation of this type of cladding and its substrate, with the aim of achieving a better quality and less costly built environment. [Copyright &y& Elsevier]

Abstract: An application of a factor method for stone cladding directly adhered to the substrate is proposed. The quantification of the reference service life and of the sub-factors that influence its durability is described. The methodology proposed is based on a survey of the degradation state of 140 cladding systems. As an innovation to the factor method and in order to overcome some of its well-known shortcomings a multiple linear regression analysis is proposed to identify the most relevant sub-factors that explain the degradation of stone cladding. [Copyright &y& Elsevier]

The use of service life prediction tools can allow a more rational management of the maintenance of a building and its components by supporting reduced life cycle costs of constructed assets. A study was conducted to evaluate the degradation of facades of buildings located in Lisbon, Portugal, and in which visual in-situ inspections of 140 stone cladding facades were completed. Based on this information, different models were proposed to describe the degradation of masonry stone-clad buildings and a novel approach to predicting service life was developed. A description is provided for the use of artificial neural networks to predict the service life of stone cladding of the type that is directly adhered to a building substrate. With the use of artificial neural networks an analytical expression was established to estimate the degradation of this type of cladding system. The viability of this method was then compared with other methods used for service life prediction including multiple linear regression and a graphical method. Some of the statistical parameters used to assess the performance of the various methods are described. Of these three methods, those variables that best explain the degradation of stone cladding, are identified: cladding age, distance from the sea, type of finish, and size of the stone plates. L'utilisation d'outils de prévision de la durée de vie peut permettre une gestion plus rationnelle de l'entretien d'un bâtiment et de ses composants en contribuant à des coûts de cycle de vie réduits des biens immobiliers construits. Une étude a été menée afin d'évaluer les dégradations des façades de bâtiments situés à Lisbonne, au Portugal, et dans lesquels des contrôles in situ de 140 façades à parement en pierre ont été réalisés. Sur la base de ces informations, il a été proposé différents modèles pour décrire la dégradation des bâtiments en maçonnerie à revêtement de pierre et il a été développé une approche nouvelle de prévision du cycle de vie. Il est fourni un descriptif pour utiliser des réseaux neuraux artificiels afin de prévoir la durée de vie des revêtements de pierre qui se collent directement sur un substrat de construction. Grâce à l'utilisation de réseaux neuraux artificiels, il a été établi une expression analytique afin d'évaluer les dégradations de ce type de système de revêtement. La viabilité de cette méthode a ensuite été comparée aux autres méthodes utilisées pour prévoir la durée de vie, dont la régression linéaire multiple et une méthode graphique. Certains des paramètres statistiques utilisés pour évaluer les performances des différentes méthodes sont décrits. Sur ces trois méthodes, les variables qui expliquent le mieux la dégradation des revêtements de pierre sont identifiées: âge du revêtement, distance de la mer, type de finition, et taille des plaques de revêtement de pierre. Mots clés: réseaux neuraux artificiels bâtiments dégradation durabilité façades entretien prévision de la durée de vie revêtement de pierre [ABSTRACT FROM AUTHOR]

The Parliamentary Precinct in Ottawa, Canada, is comprised of a number of historic buildings that include the House of Commons, the Senate Chamber, the Parliamentary Library, the Peace Tower, and other buildings that pro vide offices for parliamentarians and their staff. The majority of these buildings have exterior walls that are made of solid masonry with thicknesses ranging between 400 mm and 800 mm. In some cases, special wall areas are more than 1200 mm thick and are comprised of various types of masonry materials. With winter design tempera tures of-25°C, more than 170 cm of snowfall, and numerous thaws during the five month heating season, the exterior environmental conditions acting on the exterior wall assemblies of these historic buildings are severe enough to cause masonry and mortar deterioration wherever moisture accumulates during winter months.Infrared thermographic inspections were carried out to locate and identify the causal mechanisms of moisture accumulation within masonry wall assemblies. This paper will discuss the types of thermal patterns produced by various mechanisms of heat loss and identify some of the typical areas where possible masonry deterioration occurs. Knowledge gained from these extensive investigations will be used to de velop a nondestructive test methodology to locate areas of freeze-thaw damage as part of a predictive and preventive maintenance program to reduce preservation costs of these historical structures. [ABSTRACT FROM PUBLISHER]

Bowing is an uncommon pathology that can affect marble stone cladding of building façades, causing a large permanent deflection and the degradation of the flexural and anchoring strength of the stone slabs, which can lead to the cladding falling from the façades. Moreover, the combination of bowing with wind pressure effects on the building façades can increase the risk of fracture and collapse of the stone slabs, especially if this combination is not properly evaluated during design. Motivated by a case study, this work describes a stability evaluation of a 15-year-old building façade coated with marble stone cladding affected by bowing and subjected to wind pressures. This evaluation was focused on the stone slabs, and was performed through finite element model (FEM) numerical simulations of these slabs submitted to wind pressures and through lab tests using samples of stone slabs removed from the building façade. The results obtained demonstrated stability problems on the stone slabs caused by wind pressure-induced stresses combined with the loss of strength due to aging and bowing effects, especially for slabs with larger dimensions. [ABSTRACT FROM AUTHOR]