Inspection and diagnosis system of ETICS on walls

Garcez N., Lopes N., Brito J.D., Silvestre J.

This paper presents a system to support the inspection, diagnosis and repair of external claddings of pitched roofs (ECoPiR). The aim of this system is to standardise and systematise the inspection of these construction elements to aid the experts who perform this task. Classification systems of anomalies in ECoPiR and their causes are proposed in this paper, along with the correlation matrices of anomalies-probable causes and inter-anomalies. A classification system of in situ non-destructive tests and the correlation matrix between them and the anomalies are also presented to assist the diagnosis of anomalies in ECoPiR and their causes. A set/series of approaches to carrying out repairs is proposed in this paper. They allow the maintenance and the restitution of the functional properties of ECoPiR. The information collected during the validation of the inspection system enabled individual files of anomalies, diagnosis methods and repair techniques to be built up. The implementation of this system supports the inspection activities included in the predictive pro-active maintenance strategies of ECoPiR. The standardisation of these inspections will help improve the efficiency and effectiveness of the actions put into practice when these claddings exhibit pathologic phenomena.

Silvestre J.D., de Brito J.

In this paper a classification system of the anomalies in ceramic tiling applied to building facades and their most probable causes is proposed and a field data analysis is presented. The field work included the observation of 85 ceramic tiling systems in facades via standardized inspections. A statistical analysis of the anomalies observed during these inspections and their most probable causes is presented and the main ceramic tiling anomalies are evaluated for area affected, user disturbance and most probable causes. The interpretation of this data allowed the creation of an inventory of the measures to be implemented in the design, execution and maintenance phases, in order to prevent the occurrence of anomalies, helping the practicing engineer in his daily activity.

Pereira A., Palha F., de Brito J., Silvestre J.D.

This paper presents an expert system to support the inspection and diagnosis of gypsum plasters applied to partition walls and ceilings (inner gypsum plasters – IGP). This system includes the classification of the defects that may affect IGP and their probable causes, which is complemented by the correlation matrices between defects, and between defects and probable causes. It is completed by a classification of the diagnosis methods and the repair techniques suitable for each IGP defect. Individual files containing a complete characterization of defects, diagnosis methods and repair techniques are also exemplified. This inspection system was validated through standard inspections of 119 IGP applied in walls or ceilings in 23 buildings.

Neto N., de Brito J.

An inspection and diagnosis support system is proposed for natural stone cladding (NSC) on walls and pavements in order to systemize inspections and make them more objective. The inclusion of this system in a maintenance plan aims at preventing degradation of this type of cladding and its substrate. The system is based initially on the identification and classification of defects and probable causes associated with NSC. These data are used to compile correlation matrices of defects/probable causes and defects/defects and create defect forms with relevant data on each defect. The appropriate diagnosis and repair methods are then identified and classified, and correlation matrices of defects and diagnosis methods and defects and repair methods are assembled. An individual form with relevant data is created for each diagnosis and repair method. The system proposed was validated through 128 inspections of NSC, which were afterwards subjected to statistical posttreatment and analysis.

Silvestre J.D., de Brito J.

This paper is based on an expert system for inspecting adhesive ceramic wall or floor tiling (ACT), which includes all the anomalies that may occur in ACT as well as their most probable causes. To support diagnosis, a classification of in situ inspection and testing methods is presented as well as the files that characterize them. Diagnosis tools are complemented with a correlation matrix anomaly/test method. The repair of anomalies and the elimination of their causes are supported by a classification of the repair techniques, for each one of which a characterization file is presented and by a correlation matrix anomaly/repair technique. The ACT inspection system was validated through a series of standard inspections of 155 ACT cases, also described here. Data concerning inspection, diagnosis, and repair of each anomaly type were condensed into individual anomaly files. The expert system proposed is an essential tool for the implementation of management systems for buildings, paving the way for more objec...

Mendes Silva J.A., Falorca J.

The efficiency of maintenance of ordinary buildings is quite relevant in regard to their durability and functionality. It requires an accurate method for planning the different actions involved. This paper deals with some results of one of these models, being developed at the University of Coimbra and oriented toward the maintenance of school buildings, where an External Thermal Insulation Composite System (ETICS) was adopted. The model plan, called PIMEC, was developed in an organized system using the common methods of building maintenance. It can be employed as an algorithm to create informatics applications, allowing the active procurement of component performance data throughout the life of a building. PIMEC differs from past studies in that all the information resulting from the simulated inspection and maintenance procedures in the elements can be organized with a configuration of straightforward consultation files. In order to test and validate the proposed model, it was analyzed large buildings facades covered with ETICS. This paper explains the content of some important stages and the applicability of ETICS by presenting the results of its performance behaviour analysis. Through this specific case study it is intended to show not only the potential of PIMEC but also the extraordinary advantage of slight but accurate maintenance actions over the anticipated lifetime of ETICS.

Stazi F., Di Perna C., Munafò P.

The exterior envelope of some social housing scheme buildings constructed at the beginning of the 1970s without thermal insulation has proved to be the cause of great thermal loss and condensation. At the start of the 1980s, in order to resolve these problems, our research group carried out a study which led to the introduction of external thermal insulation (on the basis of previously developed performance specifications) and verification of the thermal performance achieved. With the aim of verifying the efficacy of the intervention after 20 years and in order to assess the thermal–hygrometric performance and the state of conservation of the exterior envelope we carried out a two stage study: 1. Performance analysis carried out through monitoring and laboratory tests. 2. Formulation of hypotheses for retrofitting, assessed through simulations and parametric analysis. The results showed the efficacy and durability from the thermal–hygrometric and mechanical point of view of the external insulation applied in the 1980s. It was also possible to verify energy saving for the different types of retrofit scenarios and to identify the correct positioning of the thermal insulation on the brickwork and on the floors so as to increase the surface temperatures in winter phase.

Silvestre J.D., de Brito J.

This paper presents a proposal of an expert system for inspection and diagnosis of defects in adhesive ceramic wall or floor tiling (ACT), specifically developed for recent buildings. The system proposed includes a classification of the ACT defects and their most probable causes in different groups, as well as the relationship between defects and all the causes and inter-defects, presented in correlation matrices. The system was validated via field work that included standardized inspections of 155 ACT cases. Its main purpose is to help the inspector to be more objective in his in situ activities and, at the same time, to standardize procedures.

Flores-Colen I., de Brito J., de Freitas V.P.

Stains in rendered facades occur very frequently in recent buildings due to various causes (efflorescence, carbonation, corrosion, cracking, dirt deposition, biological colonization and others). Most of the stains are damaging. In an initial stage, these anomalies affect the aesthetics of the facade and, some types of stains, in conjunction with the presence of water, contribute to the physical degradation of the cladding. This paper presents a set of tables and correlation matrixes related with the different types of stains, their possible causes, diagnosis techniques and treatment techniques (in particular, cleaning techniques) aimed at removing the stains from the rendered facades.

Flores-Colen I., de Brito J., de Freitas V.P.

The practice of predictive maintenance (through periodic inspections) depends on the efficiency of in situ evaluations of the in-service performance of the constructive solutions, which in turn depends on a set of logical procedures inherent to a performance-based methodology and a correct diagnosis. In situ tests are a precious auxiliary tool for visual inspections, since they allow the detection of gross diagnosis mistakes, reduce the subjectivity of visual inspections and enable a more accurate assessment of the real maintenance needs. These tests have limitations, however, and depend on the technique used (often the limited precision of a technique only allows a qualitative analysis) and the experience of the practitioners. In situ tests for rendered façades include a variety of tests and techniques, most of them not standardised, and therefore a coherent and global classification is sometimes difficult to establish. In this paper a methodology for choosing the most adequate in situ techniques to diagnose in-service performance of rendered façades is proposed. The subjects of this analysis were current and expedient techniques, used in several inspections performed in different renders, within the PhD research work of the first author. These techniques are classified and also characterised in terms of the data collected (parameters measured), their contribution to understanding in-service performance (analysis of relevant properties), the degradation state (anomalies and their causes) and their relation to maintenance needs. Finally, they are compared and rated using various criteria and evaluated in terms of their adequacy for in situ assessment.

Künzel H.M.

Massive walls exposed to the natural climate without special rain protection show a dynamic moisture equilibrium governed by the alternating events of rain and sunshine. The moisture further reduces the rather low insulation level of the walls. Therefore, thermal insulation measures have to be taken in order to improve the hygienic conditions and the thermal performance of the building. The influence of interior and exterior insulations on the hygrothermal behaviour of such walls can be determined with the aid of a recently developed computer program which has been experimentally validated by comparison with field tests. The results show that an exterior insulation leads to the drying of the wall, with the drying rate depending on the vapour permeability of the insulation system. An interior insulation, however, results in a rising water content of the wall due to the decreasing masonry temperature. This effect is almost independent of the vapour permeability of the insulating material. While an exterior insulation also improves the thermal resistance of the masonry, an interior insulation has the opposite effect and increases the frost damage risk. Therefore, the interior insulation of exposed walls should be combined with rain protection measures at the facade.

Krause P., Pokorska-Silva I., Kosobucki Ł.

ETICS is a popular external wall insulation system, which is not without possible defects and damages. A frequent cause, direct or indirect, of damage to buildings is the impact of water (moisture). This article presents, among others, the results of tests of the moisture content of ETICS layers, the water absorption and capillary absorption of the render by means of the Karsten tube method, numerical thermo-moisture simulations, and tests of interlayer adhesion, in sample residential buildings. Mass moisture content testing of the wall substrate showed acceptable moisture levels (1–4%m) within masonry walls made of silicate blocks, as well as locally elevated moisture levels (4–8%m) in the case of reinforced concrete walls. Moisture testing of the insulation samples showed a predominantly dry condition, and testing of the reinforcement layer showed an acceptable level of moisture. Severe moisture was found in the sample taken in the ground-floor zone at the interface between mineral wool and EPS-P insulation underneath the reinforced layer. Capillary water absorption tests helped classify silicone render as an impermeable and surface hydrophobic coating. Tests of the water absorption of the facade plaster showed that the value declared by the manufacturer (<0.5 kg/m2) was mostly met (not in the ground-floor zone). The simulation calculations gave information that there was no continuous increase in condensation during the assumed analysis time (the influence of interstitial condensation on the observed anomalies was excluded). The tests carried out indicated the occurrence of numerous errors in the implementation of insulation works affecting the moisture content and durability of external partitions.

Tang M., Bourbigot S., Rogaume T., Bensabath T., Batiot B., Drean V.

Numerous fire disasters have involved thermoplastic expanded polystyrene (EPS) external thermal insulation composite systems (ETICS) on building façades. This study evaluates the flame-retardant efficiency of expandable graphite (EG)-blended EPS ETICS across different scales: micro-scale thermogravimetric (TG) analysis, small-scale bench tests, and large-scale LEPIR 2 tests. TG analysis confirmed EG’s primary role as a physical intumescent, with no significant chemical interactions detected. While EG effectively reduced heat penetration in both small-scale and large-scale fire tests, challenges arose from char layer detachment and oxidation at elevated temperatures (exceeding 540 °C). Despite these limitations, the EG-treated façade exhibited significantly lower peak temperatures compared to the untreated control in the large-scale LEPIR 2 test, with a measured temperature difference of approximately 470 °C. These findings demonstrate the potential of EG to enhance the fire safety of EPS ETICS. The small-scale test bench proved effective for preliminary material screening, providing valuable insights into ignition resistance and flame-retardant properties before proceeding to more resource-intensive large-scale evaluations.

Hrischev L., Conev I.

Abstract The durability of external thermal insulation composite systems and their resistance to wind load mainly depends on the resistance of plastic anchors by means of which the systems are fixed to the substrate. A large part of the facade walls are made of reinforced concrete and various types of masonry units. This article presents an experimental study of the resistance of plastic anchors for ETICS, with different types of base materials, typical of the facade walls of buildings implemented in Bulgaria. The resistance of anchors installed in base materials with different characteristics of hollow masonry units, solid masonry units, concrete base and autoclaved aerated concrete units was investigated. As a result of the study, it was found that the resistance under tension force of the plastic anchors was the highest for base of concrete, solid clay masonry units and high-density autoclaved aerated concrete. It was found that with the different types of masonry units, as the compressive strength of the base increases, the resistance of the plastic anchors also increases.

Xie Y., Zhou T., Chen Z., Li C., Qiao W.

Exterior wall enclosure systems in steel-frame residential buildings are prone to extensive cracking and detachment under wind loads. This study, through research and comparison of commonly used materials, identified the exterior wall panel system with the optimal comprehensive performance. To assess the wind load resistance of this system, 11 sets of tensile tests were conducted considering anchor bolt quantity and the bonding rate parameters between autoclaved lightweight concrete (ALC) panels and rock wool boards. The research investigated the failure modes, load-bearing capacity, and failure mechanisms of the external wall panel system under wind suction loads. Based on the experimental findings, a simplified finite element simulation method was proposed and subjected to parameter analysis. This analysis explored the impact of anchor bolt quantity and layout. The research indicates that under tensile loads, the external wall panel system primarily experiences interfacial damage between rock wool boards and coating mortars. Its load-bearing capacity consists of the net bonding force between rock wool boards and finishing layers, as well as the mechanical force between fiberglass mesh and anchors. The load bearing capacity can be enhanced by strengthening the overall integrity of the system and by expanding the contact area between the fiberglass mesh and the anchor plate, with specific structural measures such as increasing the number of anchor, the bond ratio, and the diameter of the anchor plate. The arrangement of anchors has a minor impact on the load-bearing capacity of the external wall panel system but significantly affects the deformation of rock wool boards. Based on experimental and finite element studies, a simplified calculation method for the tensile load-bearing capacity of external wall panels for engineering applications was further developed and proven to be accurate through comparison with experimental results.

Alshaghdari M.E., Jamaluddin M.H., Sabrah A.E.

Sudoł E., Piekarczuk A., Kozikowska E., Mazurek A.

Fire barriers are used to reduce the risk of fire spreading over façades. External thermal insulation composite systems consist of mineral wool strips embedded in a layer of another thermal insulation material. A system configured in this manner, beyond standard solutions, can be more susceptible to environmental factors. In this study, an expanded polystyrene-based system with a mineral wool fire barrier was subjected to weathering conditions. In view of climate change, nonconventional long-lasting exposure simulating the effects of intensive atmospheric factors was applied. Two exposure sequences were used, each covering 80 cycles of heating and wetting, five cycles of heating and cooling, and 30 cycles of wetting, freezing, and thawing. Significant changes were observed in the first sequence. The second sequence caused rendering system cracks wider than 0.2 mm. This indicated a loss of watertightness. A new approach of 3D scanning with inspection analysis was used to assess the deformations. It showed deformation amounted to 0.7 mm within the MW strip. The methods used previously did not allow this level of deformation to be recorded.

Piekarczuk A., Sudoł E., Mazurek A.

Vidales-Barriguete A., Piña Ramírez C., Barriguete R.V., Arrebola C.V., Aguilera Benito P.

This study emerged from the necessity to analyze the most effective energy-saving strategies within the current real estate market and substantiate their application with empirical data. Undoubtedly, the adoption of External Thermal Insulation Composite Systems (ETICSs) stands out as one of the prevalent approaches. This article presents temperature-monitoring data collected on-site from the facades of two single-family homes initially constructed with identical compositions, materials, construction dates, locations, and orientations. The thermal envelope of one home underwent rehabilitation using the ETICS, while the other remained in its original state. Continuous temperature recordings on the southern and northwestern facades of both homes were conducted using thermocouples over a 15-day period. The data analysis yielded insights into facade performance before and after this rehabilitation approach. The findings suggest that the implementation of ETICS results in more stable interior temperatures, significantly reducing indoor temperatures in comparison to outdoor conditions, leading to a notable decrease in heat energy loss. Consequently, this research underscores the tangible benefits of employing ETICS in building rehabilitation, emphasizing its role as a passive energy-saving strategy. By demonstrating the positive impact on thermal performance and energy efficiency, this study reinforces the vital connection between research endeavors and sustainability objectives.

Ma T., Yuan K., Xiong H., Sha B., Zhong Q., Sun L.

Abstract As a new type of thermal insulation material, ceramic-reinforced polyurethane insulation decorative board (IDB) has been applied to a certain extent, but changes in the temperature and strain between this material and the substrate wall during the aging process remain unclear. In this study, an external insulation composite system with ceramic-reinforced polyurethane IDB was subjected to 60 heat-rain cycles, and the temperature and strain at the interface between the IDB and the substrate wall were measured. The results show that the temperature of the substrate wall is about 35 °C lower than the highest temperature of the environmental box, and the temperature fluctuation of the substrate wall during 60 heat-rain cycles always maintains at about 5 °C, which indicates that the ceramic reinforced polyurethane IDB has good thermal insulation performance and durability. During the heat-rain cycles, the vertical strain varies from −750 με to + 2750 με, while the horizontal strain varies from −250 με to + 500 με, indicating that the horizontal and vertical strains have serious inhomogeneity. This local inhomogeneity may be an important reason for the aging and cracking of the IDB. The characteristics of temperature and strain could provide a reference for analyzing the synergistic effect and disbonding mechanism of the interface between the IDB and the substrate wall, and give some guidance for the design and construction of external insulation composite systems.

Chen K., Reichard G., Xu X., Akanmu A.

Azevedo A., Almeida J., Gonçalves M., Simões N., Castro N., Santos A., Tadeu A.

External thermal insulation composite systems (ETICS) are, in general, more likely to suffer from colonisation by fungi and algae than conventional walls, regardless of the nature of the biocide technology used. This results from the greater propensity of finishing coats applied on ETICS to develop surface condensation and, consequently, favourable conditions for microbiological growth. Most commonly, aesthetic degradation is the only implication. However, some severe cases can cause coating deterioration and loss of adhesion. In this work aiming to study resistance of ETICS finishing coats to fungi and algae growth, different improvement strategies based on thermal, hydrophobic, and hydrophilic approaches were exploited. In total, five different acrylic- and silicate-based formulations (without biocide) were prepared to screen the risk of condensation and biological resistance in separate small-scale laboratory tests. Based on the results obtained, selected finishing coats were applied on a large-scale ETICS wall and tested in a bioclimatic chamber capable of simulating conditions conducive to the early development of biological colonisation. The concomitant influence of biocides was also addressed at this stage. The results showed that a simple silicate-based formulation performs better than other tentative formulations tested, exhibiting a higher resistance to fungi and algae. They also suggested that incorporating glass microspheres or adding an external siloxane layer is not on its own effective in enhancing the resistance to the biological growth of acrylic- and silicate-based formulations.

Viegas C.A., Borsoi G., Moreira L.M., Parracha J.L., Nunes L., Malanho S., Veiga R., Flores-Colen I.

External Thermal Insulation Composite Systems (ETICS) are frequently used to enhance the energy efficiency of the built environment. However, stains of presumable biological nature are often detected shortly after application, causing cladding defacement and altering the building aesthetics. To address which microbiota could contribute to these biodeterioration related color/aesthetic anomalies, samples collected from stains detected on the surface of building facades with ETICS in three residential sites in Lisbon, Portugal, were analyzed through microbiological culture-dependent technique and culture-independent amplicon DNA high throughput sequencing taxonomic profiling. The obtained data provided a comprehensive description of microbial communities assigned to diverse taxa of the major microbial groups of heterotrophic bacteria, fungi, cyanobacteria, and microalgae (through DNA plastid detection) in the sampled stains. Based on that, we propose that new microorganisms could be added to the list of bio-susceptibility testing organisms in ETICS. Furthermore, microbiota diversity depended more on facade location and cardinal orientation than on ETICS material composition. Overall, this study reveals the unique microbial communities of color/aesthetic biodeterioration stains in ETICS facades, unlike those of other surfaces, and the associated environmental dynamics.

Parracha J.L., Veiga R., Flores-Colen I., Nunes L.

The identification of the main degradation agents and knowledge of the degradation mechanisms and long-term performance of ETICSs are of fundamental importance for the sustainable and efficient use of these systems. This review article presents the state of the art related to the durability of ETICSs, defining the required bases for their sustainable and efficient use. The aim is to identify the most common anomalies detected on ETICS façades and their causes, to overview the performance of ETICS, their performance parameters and requirements and to identify the most significant degradation mechanisms and the related failure modes. The results show that ETICS application is a key aspect in the performance and durability of the system, since most of the anomalies can be prevented with proper design, execution and appropriate assembly of the system components. The greatest drawbacks lie in dealing with enhancing the water resistance over time, which leads to extensive cases of anomalies, and improving the mechanical and thermal performance during the life cycle. Further research is needed to evaluate the synergistic effect of several degradation agents and mechanisms toward a development in optimized durability assessment methodologies for ETICSs.

Saba P., Honorio T., Brajer X., Benboudjema F.

In France, buildings’ heating systems represent 45% of the total energy consumption and are responsible for 27% of greenhouse gas emissions. Thermal insulation, including the External Thermal Insulation Composite System (ETICS), has a big impact on energy consumption and CO2 emissions, increasing, at the same time, the thermal comfort of the residents and decreasing their energy bills. The fiberglass mesh-reinforced rendering mortar is used as the external protective layer of ETICS. Many defects may attain the ETICS, including the cracking of the rendering mortar. The cement-based mortar undergoes chemical, thermal, and hygral strains, which, when restrained, cause stress that may attain the material’s tensile strength and cause the mortar to crack. The fiberglass mesh is proposed as a reinforcing solution for cracking. Here, we focus on the cracking development in the reinforced mortar layer using experimental techniques. To understand the crack initiation and propagation in the reinforced mortar layer and the role of the fiberglass mesh as reinforcement inside the mortar, a new mechanical inclined 4-point bending set-up is developed and performed using in-situ X-ray tomography. The latter allows observing the cracks inside the mortar sample, shedding light on the reinforcement mechanisms of the fiberglass mesh and its impact on the initiation and propagation of the cracks.

Feltes J., Borsoi G., Caiado P., Dionísio A., Parracha J., Flores-Colen I.

External thermal insulation composite systems (ETICS) have been widely adopted for improving the thermal comfort of building facades. Although these systems are commonly subjected to vandalism in urban areas, no protocols for the removal of graffiti on ETICS have been yet systematically defined. In this work, aerosol graffiti sprays (blue and silver) were applied on ETICS with different compositions and then removed through chemical (alkaline graffiti removers) and/or mechanical methods (brushing). The moisture transport properties and the aesthetic features of ETICS specimens were characterized prior and after graffiti removal, aiming at assessing the effectiveness and compatibility of the cleaning action. Results show that the effectiveness of graffiti removal strictly depends on the type of aerosol graffiti spray and of ETICS surface. The use of chemical or mechanical methods can lead to severe damage on systems with EPS-based thermal insulation layer and/or silicate or lime-based finishing coats, with an increase of the water absorption and alteration of the chromatic coordinates.