Science and engineering intermingle in the area of construction. Engineering works, often of great dimensions and design life cycle of many decades, have to be designed on a scientific basis since the safety of hundreds of users depends on their design. The task of scientific institutions is to define the construction performance within categories that correspond to the contemporary level of knowledge and technology. A construction appraiser who speaks out in a way that ensures unquestionable competence about the performance of elements and buildings (existing and under construction), should be convinced of the scientific basis of his opinions. A comparison of construction sections vs. basic requirements presents an archetype of the science of construction. A matrix of the science of construction reveals its multi-faceted nature; if related to time-the issue of durability has to be considered, and if related to the scale-the complexity. Defining the construction performance in terms of technical features is a constant search for a relationship between the material model and the usability model of a building. The construction industry uses a lot of "rules of thumb", more than any other sector of technology. In the era of computer-aided design, CAD, and building information modelling (BIM), those rules of thumb remain invaluable verification tools.