A sustainable construction develops the idea of low embodied energy, reduced greenhouse gas emission and water consumption, low operational and maintenance costs, durability, safety, adaptability and comfort. Some important aspects concerning building sustainability are presented in the book. In the first part, the concept of sustainable development and its position in the scientific world is discussed. The main aspects of three sustainability certificates (BREEAM, LEED and DGNB) are evaluated; a comparison between these tools is realized and some important ideas are underlined. In the second part, the authors proposed two proper models to evaluate the sustainability of a building or strengthening solution. The first one is a global model based on a scoring system for each dimension: ecological, economic and social. The second model is based on a simple formula and takes into account numerical values of the criteria. According to this model, the Building Sustainability Index (BSI) is obtained which is a facile instrument for civil engineering approach. The two evaluation models are applied on two case studies: a typical family dwelling and a strengthened element.