The article presents the analysis of the thermal performance of an EPS-based system finished with different plaster coatings. The analysis is based on the results achieved at the field site station. ...The analysis took into account the type of plaster, its texture and the orientation of the exterior wall finish relative to its facing which the moisture content inside the EPS and under the plaster coating is also dependent. It is noted here that the accumulation of moisture takes place within the expanded polystyrene. It was also found that the stabilization of moisture levels in the insulation material depends on the type of external plaster coating. The actual thermal performance of the insulation material was analyzed using the results of the evaluation of the moisture properties in the expanded polystyrene under the plaster coating at the field site. The moisture results confirm that there is an accumulation of moisture in the insulation material, which has a significant impact on the value of thermal resistance, with the largest differences found in the north and west facing exterior wall finishes.
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•Assessment of water resistance, mould susceptibility and surface properties of ETICS.•Moisture content influence on the thermal conductivity of the insulation layer.•Definition of ...ETICS performance parameters.•Contribution towards the development of ETICS with improved durability.
The use of External Thermal Insulation Composite Systems (ETICS) significantly increased in the last decades due to their enhanced thermal properties, low installation cost and ease of application, not only in new constructions but also for thermal retrofitting of building facades. These multilayer rendering systems are constantly exposed to weathering agents and anthropic factors which can lead to physical-mechanical and aesthetical anomalies and thus affect their durability. However, possible synergetic effects among these agents are often neglected by international technical documents on the evaluation of the effectiveness and durability of ETICS. With the aim of filling this gap, moisture transport properties (capillary water absorption, water vapor permeability, water absorption under low pressure, and drying kinetics), thermal conductivity, mould susceptibility and surface properties (color, gloss, and roughness) of twelve commercially available ETICS were assessed and discussed. Possible links between these factors were analyzed and ETICS performance parameters were defined. Results demonstrate that a deeper knowledge of the correlation among ETICS properties can effectively contribute to the evaluation of the efficiency and long-term durability of these systems.
•The use of vacuum technology can improve the energy performance of buildings.•VIP products available for external insulation and case studies are discussed.•Design and installation, durability and ...economic viability are the main challenges.•High cost and service life are key-factors for the wide-scale use of vacuum panels.•Guidelines for performing an adequate evaluation of this solution is proposed.
The worldwide demand for energy efficiency calls for improvements in the thermal performance of buildings. As a result, there is a growing interest in the use of high-performance insulation materials such as vacuum insulation panels (VIPs). Due to their low thermal conductivity, high insulation levels can be achieved with thinner walls than is possible with conventional thermal insulation materials. An interesting solution might be to combine a vacuum insulation panel with the well-known external thermal insulation composite system (ETICS). However, in terms of practical application and long-term performance, this solution needs to be looked into further.
This paper aims to review the challenges posed when using VIPs in the external insulation of buildings. First, the main advantages and anomalies of ETICS are identified, after which the available VIPs solutions intended for external insulation are explored. Some case studies are presented and the main conclusions that may be drawn from these are highlighted. The difficulties of incorporating VIP products into ETICS are addressed. These include adapting/introducing covering layers to allow flatness and facilitate the handling of the products, defining and assessing a suitable fixation system, and ensuring the connection between construction elements. The main concerns regarding the ETICS with a VIPs solution are also discussed, such as edge thermal bridging, service life performance and installation, and the economic viability of the solution. Finally, we propose guidelines for performing a good evaluation of ETICS solutions that use VIPs.
External Thermal Insulation Composite Systems (ETICS) are multilayer solutions which provide an enhanced thermal performance to the building envelope. However, significant anomalies can be detected ...on ETICS facades, in some cases shortly after the application of these systems. This study intends to evaluate and compare the durability of six commercially available ETICS after two years of outdoor exposure at both urban and maritime conditions in Portugal. The systems were characterized by means of non-destructive testing (i.e., visual and microscopic assessment, water transport properties, thermal conductivity, surface roughness), thus allowing to evaluate the performance loss throughout natural aging. The bio-susceptibility and aesthetic properties (color and gloss) were also investigated. Results showed that the performance and durability of the complete system is significantly affected by the rendering system formulation. The lime-based specimens obtained the highest rate of mold development after one year of aging in a maritime environment, becoming considerably darker and with lower surface gloss. Fungal analysis of this darkish stained area indicated the presence of mold species of the genera Alternaria, Didymella, Cladosporium and Epicoccum, and yeasts of the genera Vishniacozyma and Cystobasidium. An increase of both capillary water absorption and water vapor permeability was also registered for the aged lime-based specimens. Acrylic-based systems obtained lower capillary water absorption after aging and greater dirt deposition on their surfaces, especially in urban conditions. These systems had also higher color variation and surface gloss decrease and slightly higher mold growth, when compared with those aged in a maritime environment. Finally, no mold growth was detected on the silicate-based specimens after two years of aging. However, these specimens obtained higher capillary water absorption and lower vapor permeability after aging, possibly leading to moisture accumulation within the system. Results contribute towards the development of ETICS with enhanced performance and durability.
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•ETICS were exposed for two years at both urban and maritime environments in Portugal.•The durability was assessed considering the ETICS condition throughout natural aging.•The bio-susceptibility and the aesthetic properties after aging were investigated.•The durability of the complete system was significantly affected by the rendering system formulation.
Different envelope solutions are used for the implementation of thermal insulation requirements, assuming that a solution that insures good thermal insulation will automatically insure good sound ...insulation. The use of External Thermal Insulation Composite System (ETICS) may be one of many solutions. The aim of the experiment was to evaluate how thermal insulation (EPS and mineral wool) and coating (plaster) layers of ETICS influence on sound and thermal insulation of a basic element (wall). The experimental results showed that added thermal insulation (EPS and mineral wool) and coating (plaster) layers of ETICS can influence the sound and thermal insulation of the wall differently. The addition of a thermal insulation layer of ETICS changes sound insulation (increases up to 4 dB) of wall with mineral wool, but in using EPS, has no significant influence. The addition of a coating (plaster) layer over the thermal insulation material layer allows an increase in sound insulation in both cases from 3 dB to 7 dB, but does not change the thermal insulation. The addition of a layer of thermal insulation changes the thermal insulation of basic wall – it increases up to 4.88 m2 K/W with EPS and up to 5.09 m2 K/W with MW, respectively. The influence on sound insulation depends on the type of thermal insulation material used, the presence or absence of a coating (plaster layer) and its thickness, while the influence on thermal insulation does not depend on these factors. It only depends on the presence of the thermal insulation layer.
Pore structure is an important factor that affects both vapor adsorption and water absorption performances of the expanded perlite insulation mortar. This study aims to explore the change in the pore ...structure of the expanded perlite insulation mortar in heat-rain cycles and investigate the effects on capillary water absorption and vapor adsorption performances. The expanded perlite insulation mortar specimens was subjected to 160 heat-rain cyclic test, and the distribution characteristics of the pore structures of the specimens after different heat–rain cycles in vacuum saturated water absorption, capillary water absorption, and vapor adsorption processes were measured via nuclear magnetic resonance. According to the test results, the pores with a size of greater than 1 μm in the expanded perlite insulation mortar determined the variation in total pores. The pore size can be classified into different ranges according to the performance in capillary water absorption and vapor adsorption. The calculated results of the fractional dimension suggest that the structure variation rules of different types of pores can be characterized by the fractional dimension. The relationship between the macro-performance parameters and the micro-structure can be established by using the fractional dimension as the linkage to provide reference for the hydrothermal evaluation of the whole expanded perlite external thermal insulation composite system.
•The evolution of the pore structure of ETICS EP was measured by NMR.•The variation of adsorption and water absorption properties in aging process was analyzed.•The fractal dimension was used to characterize the pore structure of ETICS EP.
This study evaluated the durability of three innovative multilayer insulation systems incorporating thermal mortars with EPS aggregates and silica aerogel granules after hygrothermal accelerated ...aging and one year of natural aging at an urban site in Portugal. The loss of performance was assessed after the accelerated aging and every three months of natural aging using non-destructive testing. Chemical-morphological analyses were also carried out prior to and after accelerated and natural aging. Results obtained after accelerated and natural aging were compared, thus contributing towards a deeper understanding of possible synergistic effects of several degradation agents and mechanisms on the long-term durability of multilayer insulation systems. The Coffin-Manson equation showed that the accelerated aging procedure (∼13 days of heat/rain cycles and 5 days of heat/cold cycles) adopted herein corresponds to approximately 11 years of natural aging in typical urban conditions. The results show a significant increase in capillary water absorption and drying capacity after aging. Extensive surface microcracking was observed after accelerated aging and after 3 months of natural aging, especially in the systems facing North. Traces of biological growth were detected on both the artificially and naturally aged systems, whereas aesthetic alterations were more pronounced in North-oriented specimens after 3 months of exposure, with significantly lower surface gloss and a darker tone. On the other hand, color change cannot be detected in the artificially aged systems (ΔElab* < 2), due to the lack of degradation agents such as pollutants or UV radiation that were not included in the accelerated aging procedure.
•The durability of multilayer insulation systems was assessed after accelerated and natural aging.•The accelerated aging procedure corresponds to ∼11 years of natural aging in typical urban conditions.•A significant increase in capillary water absorption was registered after aging.•Traces of biological growth were detected after accelerated and natural aging.•Degradation agents identified in long-term field exposure should be considered in optimized accelerated aging procedures.
Biocide-free renders and coatings for external thermal insulation composite systems (ETICS) are now long-established on the market and contribute notably to the improvement of ETICS’ environmental ...properties. A low likelihood of microbiological growth is a relevant criterion when choosing ETICS. We examined whether a previously developed accelerated weathering test would be able to determine the ETICS’ resilience to microorganisms and be suitable as a standard instrument to check the fitness for use of biocide-free ETICS renders and coatings. 15 different combinations of renders and façade coatings, including both new and established products, were tested for 15 weeks under accelerated weathering. The used lifelike weather conditions derived from climate data on an average autumn day in Holzkirchen, Bavaria are favourable for microbiological growth. Specimens were inoculated with a spore suspension containing fungi and algae typical for buildings derived from the institutes' own collection of building-relevant organisms. The results clearly show that biocide-free ETICS’ coatings can be highly resistant to microbiological growth. Of the tested product variants, only two showed low or medium resilience. Additionally, we measured the formation of surface water condensation. Knowledge of the amount of condensation water accumulated during dew point shortfall usually confirms the results of the accelerated weathering test. However, contradictory results also exist. This can be explained by different evaporation times of condensation water on the surface of renders. The evaporation times depend on the render's inherent properties. Our results confirm that the used accelerated weathering setup is a suitable standard instrument to assess and compare the resilience of biocide free ETICS to microbial infestation.
•An accelerated weathering test based on lifelike weather conditions can verify the resilience of biocide-free ETICS.•ETICS’ resilience depends on the amount of condensation water in the plaster system.•For ETICS’ functionality, the timeframe of the drying process is important.•Most biocide-free ETICS on the German market show high resilience.
•Assessment of water performance, bio-susceptibility, and surface properties of aged multilayer thermal systems.•A significant loss of surface hydrophobicity occurred after ageing.•Artificial ageing ...strongly influenced the drying kinetics of the systems.•Traces of mould growth were observed on the artificially aged systems.
Multilayer external wall thermal insulation systems are widely used in new constructions and for the retrofitting of building façades. Despite the increasing use as constructive solution, significant anomalies have been frequently identified on these systems only few years after their application, raising questions on their long-term durability. This paper focuses on the effects of one-year natural ageing and artificial ageing through hygrothermal cycles (heat/rain and heat/cold) on the water performance (capillary water absorption and drying kinetics), bio-susceptibility (mould development) and surface properties (colour, gloss, and roughness) of four multilayer external wall thermal insulation systems (three ETICS and a thermal rendering system). Results showed a significant loss of surface hydrophobicity after ageing. Considering the 24 h water absorption results, an increase up to 73% and 432% was obtained for the naturally and artificially aged systems, respectively, and when compared to the reference unaged systems. The drying kinetics was affected by ageing, with increases of the drying resistance ranging between 47% and 122% after artificial ageing. Traces of mould growth were observed on the artificially aged systems; however, no growth was detected on either the unaged or the one-year naturally aged systems. Substantial colour change for all systems after ageing was observed, confirming aesthetic alteration. Results contribute towards the development of implemented artificial ageing protocols, as well as for the delivery of multilayer thermal systems with enhanced performance and durability.
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