A screen (15) applied to overlay a gutter (14) on an outside edge of a roof (11) of a building. The screen comprises a panel (15) of generally planar mesh affixed along a first edge to the roof (11) and along the opposite edge of the panel to the top outside edge (18) of the guttering (14). The mesh is formed of moulded plastics material and the panel (15) has an electrically powered heating strand (50) extending along the panel in the direction of said first edge. A screen (15) applied to overlay a gutter (14) on an outside edge of a roof (11) of a building. The screen comprises a panel (15) of generally planar mesh affixed along a first edge to the roof (11) and along the opposite edge of the panel to the top outside edge (18) of the guttering (14). The mesh is formed of moulded plastics material and the panel (15) has an electrically powered heating strand (50) extending along the panel in the direction of said first edge.