@ A window frame panel assembly for arrangement in an inclined roof surface comprises opposed pasallel side plates (1, 2) as well as top and bottom members (3, 4) of'plate material. The vertical side plates (1, 2) have parallel first and second longitudinal side edges (1a, 1b) anti end edges (1c, 1d) comprising a first part (5, 6) at riglit angles to a first longitudinal side edge (1a) and, on the remainder of the width of the side plate (1, 2) a second part (7,8) inclined with respect to the opposite longitudinal side edge, said second parts diverging against said second side edge to form angles therewith corresponding to the roof inclination. The top and bottom members (3, 4) are formed as curved or bent plate profiles of a cross-sectional shape corresponding to respective ones of the opposed end edges (1c, 1d) of the side plates (1, 2).

After assembling, the side plates and top and bottom members (1-4) of the panel assembly into a rectangular frame structure adaption to the actual roof thickness may be performed by cutting-off from said members at the external side of the panel assembly.