A method for mounting a roller screen, in particular in the form of an insect net or the like, for shielding a building aperture, in particular a roof window area, in an inclined wall, which roller screen comprises: a top casing comprising a rear surface adapted for abutting the inclined wall in a mounted condition of the roller screen, a front surface adapted for facing away from the inclined wall in a mounted condition of the roller screen, and an upper surface adapted for connecting the rear surface and the front surface, a bottom element, first and second side rails (6, 7), a mounting bracket comprising a first leg adapted for abutment against the inclined wall, a second leg extending at angle to the first leg, and a third leg extending from the second leg either in the same direction as the first leg to form a substantially U-shaped configuration, or in an opposite direction to the first leg to form a stylized inverted S configuration, and a screening body, the method comprising the steps of: a) assembling a rectangular frame comprising the top casing, the bottom element and the first and second side rails (6, 7) such that the top casing and the bottom element extend substantially in parallel to each other, and that the first and second side rail (6, 7) extend substantially in parallel to each other and connecting the top casing and the bottom element, b) mounting the mounting bracket on an inclined wall of a building adjacent to a top wall of the building aperture, c) bringing the top casing of the rectangular frame into engagement with the mounting bracket in such a way that the rectangular frame is carried by the mounting bracket and is allowed to hang free, extending substantially vertically from the mounting bracket, and d) bringing the rectangular frame into abutment with the inclined wall along all of the periphery of the building aperture. a top casing comprising a rear surface adapted for abutting the inclined wall in a mounted condition of the roller screen, a front surface adapted for facing away from the inclined wall in a mounted condition of the roller screen, and an upper surface adapted for connecting the rear surface and the front surface, a bottom element, first and second side rails (6, 7), a mounting bracket comprising a first leg adapted for abutment against the inclined wall, a second leg extending at angle to the first leg, and a third leg extending from the second leg either in the same direction as the first leg to form a substantially U-shaped configuration, or in an opposite direction to the first leg to form a stylized inverted S configuration, and a screening body, the method comprising the steps of: a) assembling a rectangular frame comprising the top casing, the bottom element and the first and second side rails (6, 7) such that the top casing and the bottom element extend substantially in parallel to each other, and that the first and second side rail (6, 7) extend substantially in parallel to each other and connecting the top casing and the bottom element, b) mounting the mounting bracket on an inclined wall of a building adjacent to a top wall of the building aperture, c) bringing the top casing of the rectangular frame into engagement with the mounting bracket in such a way that the rectangular frame is carried by the mounting bracket and is allowed to hang free, extending substantially vertically from the mounting bracket, and d) bringing the rectangular frame into abutment with the inclined wall along all of the periphery of the building aperture. a) assembling a rectangular frame comprising the top casing, the bottom element and the first and second side rails (6, 7) such that the top casing and the bottom element extend substantially in parallel to each other, and that the first and second side rail (6, 7) extend substantially in parallel to each other and connecting the top casing and the bottom element, b) mounting the mounting bracket on an inclined wall of a building adjacent to a top wall of the building aperture, c) bringing the top casing of the rectangular frame into engagement with the mounting bracket in such a way that the rectangular frame is carried by the mounting bracket and is allowed to hang free, extending substantially vertically from the mounting bracket, and d) bringing the rectangular frame into abutment with the inclined wall along all of the periphery of the building aperture.