In many instances paints interlayers delamination is attributed either to environmental or to application reasons. The composition as well as the structure, including morphology are always given for granted. The resin to pigment ratio, the surfactants, the quality of pigments and fillers (dimensions, shape, wettability, reactivity, homogeneity of distribution…) are not clearly required, defined and consequently checked. A fundamental article appeared in 1949 defining PVC and CPVC. In the following, it was quoted several times but not many improvements in the subject were shown: the subject was considered as obvious and unquestionable. We have tested some cases of coating delamination from big steel structures where other causes were either absent or not dominating if paint features were not taken into account. Many features of paint composition and structure were analyzed with both SEM and EDAX and a comparison with a carefully formulated paint was carried out.