Hat-sections are often used to experimentally investigate building sheeting subject to a concentrated load and bending. In car doors, hat-sections are used for side-impact protection. For building sheeting, two types of crushing (by moving yield lines) exist. This article shows that cross-section behaviour can partly be used to explain total section behaviour. This is shown by finite element models of a very small strip dx of the hat-section. The quality of the finite element models for describing moving yield lines is verified.