The External Thermal Insulation Composite System (ETICS) is one of the most common passive strategies to obtain energy savings in existing buildings. Despite previous studies dealing with ETICS durability in real building case studies or involving accelerated ageing tests in climatic chambers, little progress has been made in the knowledge of the long-term durability and energy efficiency of the system. In this work, following previous experiments on ageing cycles, different climatic chambers are used to accelerate performance decay by simulating the natural outdoor exposure to assess the thermal transmittance decay of a building wall. After evaluating through laboratory tests the decay of the thermal performances of grey expanded polystyrene sintered (EPS) and polyurethane, the results are applied to an existing building. The case study building is virtually located in three different Italian climatic zones and an evaluation in terms of thermal transmittance values and their influence on heating energy consumption is made by using the dynamic simulation software DesignBuilder. The results show no significant variations during ETICS service life; the thermal performances are reduced little over time and therefore there is an increase in consumption for building heating of about only 2% after a time t1 equal to 8 years.

The External Thermal Insulation Composite System (ETICS) is a common cladding technology that is widely used thanks to its well-known advantages. Despite previous studies dealing with ETICS durability in real-building case studies or involving accelerated ageing tests in climatic chambers, little progress has been made in the knowledge of the long-term durability of the system. In order to realize optimized maintenance plans for this component, the durability of the whole system, and of the most-used insulating materials for the ETICS (i.e., cork, polyurethane, rock wool, glass wool, grey EPS, and fiberfill wood), has been investigated. Based on previous experiments on ageing cycles, different climatic chambers were used to accelerate performance decay by simulating natural outdoor exposure in order to assess different physical and thermal characteristics (thermal transmittance, decrement factor, time shift, water absorption, thermal resistance, and conductivity). Recorded trends show that materials with lower thermal conductivity exhibit lower performance decay, and vice versa. The durability of the ETICS with different insulating materials (as the only variable in the different samples) was evaluated in order to quantify service life and then correctly plan maintenance interventions. Life-cycle assessment must take into account service life and durability for each material of the system. A higher durability of insulating materials allows for the execution of less maintenance interventions, with the loss of less performance over time. This study shows the physical and thermal behavior of the ETICS during its service life, comparing the differences induced by the most-used insulating materials. As a result of accelerated ageing cycles, the analyzed ETICS reveals a low grade of decay and measured performances show little degradation; for thermal conductivity, differences between the measured and the declared conductivities by technical datasheet were observed.

The building sector is affected by a significant confusion between the concepts of sustainability and energetic efficiency: indeed, both the paradigms have the aim of safeguarding the planet, but the strategies to enact them certainly follow two different paths, often in contrast between them. The design of building envelopes has definite performance requirements, according to the current framework, but in any case the technological choices to fulfil them are not univocally determined. As an example, the objective of obtaining building envelopes with low transmittance can be reached by a huge number of typologies of solutions and materials, but of course the possible evaluations in terms of sustainability may in some cases show results that overturn the energetic assessment. Also, considering the strict relation that exists between durability (also in terms of resilience) and sustainability, it can be concluded that the most correct tendency for materials and products can be – more in general – defined as environmental efficiency, the so-called eco-compatibility. Taking moves from the scientific literature on products and materials, both from the point of view of sustainability, and from that of durability and resilience, this work proposes a number of comparative evaluations that analyse the main systems and components of the external envelopes: built-up roofs and roof systems, opaque and transparent walls, ground floor slabs, doors and windows. LCA analyses, durability assessments and considerations on resilience carried out on the abovementioned systems and components provide very interesting results to guide designers towards more conscious choices, aimed to integrate the different (and sometimes contradictory) aspects that allow to realize energetically and environmentally efficient buildings.

The performance decay of a building component is influenced by a huge variety of parameters, interacting between them and determining different results in terms of service life and performance over time. For this reason, evaluating and modeling the performance of a component requires the comprehension of the way and the measure the single factors affect it, and turning this into an analytical model is a very complex operation. Moreover, components of existing buildings are subjected to an additional incognita: the characteristics and the durability of the materials, which is hardly a certain information, and can vary between similar buildings, affecting the accuracy of the evaluation. This study, conducted according to the guidelines of ISO 15686:7 code, investigates on a common solution for interventions on existing buildings, the ETICS, surveying their current performance degree through thermographic camera tests. The aim is to appreciate the difference in the performance decay between different façades of the same buildinga homogeneity that allows to estimate this parameter alone-in order to reach an analytical expression of the variation of performance decay according to the difference in the exposure. The sample is constituted by buildings of large dimensions and well-known original projects and details of successive interventions, located in the city of Naples. The data obtained with in-field measurements were subjected to statistical analysis, to allow the quantitative determination of the impact of this parameter.