# Atlas of Defects within a Global Building Inspection System
## 1 Introduction  
### Background, Problem and Purpose  
The built environment has a central position in the pathway to achieve a sustainable development [1]. Several issues may be key in this context, such as urban and spatial planning, energy use, greening, material selection, design strategies, thermal comfort and indoor air quality. Additionally, building maintenance has a relevant role. Maintenance strategies, if well planned, prolong the service life of buildings, hence contributing to their constant reuse, reducing the need for new buildings and decreasing construction and demolition waste. A global reduction of consumption of resources is thus possible through effective building maintenance. Building maintenance plans should include a combination of proactive (preventive or predictive) and reactive strategies [2]. Nevertheless, proactive strategies are preferred, as reactive maintenance tends to result from more severe damage to buildings, thus involving higher costs. Although predictive proactive strategies are those that depend the most on building inspection, to assess the real state of building elements, all strategies benefit from building inspections in some way [3; 4]. In this context, inspection results are paramount, as they are used to determine the type and boundaries of repair actions, thus influencing the efficiency of those actions and global costs. To make inspection procedures as unbiased as possible, they have to be systematised in order to increase objectivity and improvethe diagnosis results. That is the role of building inspection systems. If such systems are adopted, procedures are standardised, the collection of information is organised, the technical language is homogenised, communication is improved, inspection activities become more agile and the whole process becomes less dependent on the surveyors' knowledge and experience [5]. First and foremost, the inspection results will be more reliable. The architecture of building inspection systems should include methods to quantify the severity of degradation and the urgency of repair of building elements, as they are associated with maintenance optimisation [6; 7; 8]. The quantification of the degree of deterioration of building elements allows prioritising interventions [9] to comply with functional requirements at a minimal cost [10]. While systematising the knowledge on building pathology, a research team from Instituto Superior Tecnico (IST), University of Lisbon (UL), developed a set of expert inspection systems, each one referring to a specific type of building element/material. These systems include classification lists of defects, their causes, diagnosis methods and repair techniques, as well as correlation matrices between defects and the other items. However, building inspections are not usually focused on a single type of building element/material, considering the building as a whole instead. So, surveyors would have to use different inspection systems to assess the real condition of different types of building elements/materials. To pragmatically tackle this issue, a global building inspection system is under development at IST-UL based on the individual inspection systems (Table 1). The harmonised classification lists of the global system, referring to defects, their causes, diagnosis methods and repair techniques, have already been published [11; 12; 13; 14]. Additionally, each type of defect, in each type of building element/material, is given specific parameters to determine its urgency of repair [11]. Within this context, the main research question emerged: how can an expeditious tool to identify defects and their urgency of repair be achieved? This study intends to propose an atlas of defects applicable to several types of non-structural building elements/materials, trying to clarify complex issues associated with the analysis of building pathology.