# Retrofitting a Building's Envelope: Sustainability Performance of ETICS with ICB or EPS
###### Abstract  
This paper analyses the environmental, energy, and economic performances of the External Thermal Insulation Composite System (ETICS) using agglomerated insulation cork board (ICB) or expanded polystyrene (EPS) as insulation material applied in the energetic renovation of the building envelope during a 50-year study period. A comparison between ETICS using ICB and EPS, for the same time horizon, is also presented. The environmental balance is based on \"Cradle to Cradle\" (C2C) Life Cycle Assessment (LCA), focusing on the carbon footprint and consumption of nonrenewable primary energy (PE-NRe). The characteristics of these products in terms of thermal insulation, the increased energy performance provided by their installation for retrofit of the buildings' envelope, and the resulting energy savings are considered in the energy balance. The estimation of the C2C carbon and PE-NRe saved is considered in the final balance between the energy and environmental performances. ETICS with ICB is environmentally advantageous both in terms of carbon footprint and of PE-NRe. In fact, the production stage of ICB is less polluting, while EPS requires lower energy consumption to fulfil the heating and cooling needs of a flat, due to its lower U-Value, and its lower acquisition cost results in a lower C2C cost. Comparing both ETICS' alternatives with reference solutions, it was found that the latter only perform better in the economic dimension, and only for an energy consumption to fulfil less than 25% of the heating and cooling needs. This paper represents an advance to the current state-of-the-art by including all the life-cycle stages and dimensions of the LCA in the analysis of solutions for energy renovation of building envelopes. energy performance; expanded polystyrene; external thermal insulation composite system; insulation cork boards; life-cycle assessment; whole-life cost +
Footnote †: journal: Applied Softto an elastic, steam permeable and durable product, which also has excellent thermal and acoustic insulation characteristics. A solution for continuous external thermal insulation of walls of buildings is an External Thermal Insulation Composite System (ETICS). An improved energy efficiency of the envelope of new and refurbished buildings is provided by the application of ETICS as external rendering and insulation of walls. ETICS comprise an insulation board applied over the substrate (glued, mechanically fixed, or both), above which one or two thin layers of reinforced render are applied, as shown in Figure 1. The latter can also be used to glue the insulation material and should have good adherence to the substrate, high resistance to cracking, low capillarity, and significant mechanical resistance to perforation and impact [1]. ETICS can have different thicknesses and compositions, particularly concerning the percentage of organic matter of the coating layers, reinforcement materials, and fastening solutions [2]. The application of an external thermal insulation in the building allows a reduction of the thermal bridges of the building and evens out the thermal transmission coefficient throughout the facade. This technique [3] allows savings in energy, lower risks of surface condensations, an improvement of the inner thermal comfort both in winter and summer, a reduction of the external wall's thickness, and, thus, an increase of the net inner area of the construction, a reduction of the walls' weight and of the dead loads on the building, an improvement in the facades' permeability, an easier application than other techniques, and a bigger variety of the facades' colours and textures. The improvement of the energy efficiency of the external walls of new and refurbished buildings is ensured by the application of ETICS.