Flat roof structures with intermediate rafter insulation represent physically demanding constructions. Particular attention is paid to the shaded areas here. In a completed HFA research project, the beneficial effects of partial insulation in connection with partially shaded partitions were demonstrated. This approach was pursued further in this project. For this purpose, the moisture-related behaviour of partially insulated roof elements with different shading scenarios and the temperature development under PV modules were examined in field trials. In addition, hygrothermal simulations were carried out.