Abstract: A roof panel (1), which includes a support course (12) for supporting a water-impervious layer (11) or for supporting a windproof layer. The roof panel additionally includes a lower diffusionproof layer (15) and normally one insulating course (14) located in the region between the lower diffusionproof layer and the support course. The roof panel is disposed with a frame (16) which forms the outer edges (20-23) of the roof panel, in addition to which the frame along opposite edges is disposed with devices in order to affix adjacent roof panels in relation to one another and in order to affix the roof panels to a substrate (4) such as a roof truss, a support wall etc.