Deterioration model of ETICS, based on stochastic Petri nets

The evaluation of the service life and maintainability of building’s envelope elements allows finding more sustainable solutions, ensuring the long-term durability of assets and reducing the costs associated with rehabilitation activities. The development of degradation models, without considering the impact of maintenance activities, is an extremely relevant step. In this study, a model to assess the degradation of External Thermal Insulation Composite Systems (ETICS) over time is defined, based on a Petri net modelling technique. A sample of 378 ETICS, located in Portugal, is evaluated through in-situ visual inspections. The uncertainty associated with the transition between the different degradation conditions is modelled by different probabilistic distributions. The validation of the model is based on probabilistic indicators of performance, computed through Monte Carlo simulation. The model proposed allows evaluating the probability of belonging to a given degradation condition and estimating the end of the service life of ETICS.