Roofing

Are there dangers in painting lead flashing with bitumen paint?

Anonymous user 16/03/2024 - 3.32 PM

I've read that lead flashing shouldn't be painted because lead expands and contracts and so any paint on it will eventually crack and flake. Instead it's recommended that patination oil should be applied to lead flashing every three or four years to preserve the condition of the lead. Patination oil makes the lead look a slightly darker grey. My house is being clad with insulation panels followed by timber-boarding. This means the brick window cills have to be extended, as there's no more than 1cm between the top of the brick cills and the weep-holes in the uPVC window-frames. So a batten is going to be nailed to the front of the brick cills, to extend their protrusion away from the new surface of the house, and then the cills will be dressed with lead. The brick cills protrude 10cms horizontally from under the window-frames, then they drop about 10cms diagonally forward, and then they drop vertically about 10cms. So when the house is looked at from the road, the cills appear to be about 20cms in height, which means quite a substantial strip of horizontal grey lead will be visible beneath each window. So I would like to know if there is any acceptable way of darkening or blackening the lead dressings on these cills. Could the lead be painted with black bitumen paint, which presumably is flexible and perhaps will not crack as the lead expands and contracts beneath it. But I haven't found any advice anywhere online saying that using bituminous paint on lead is OK. I've also wondered whether patination oil, which is clear, could be darkened or pigmented, without negative effects. All advice will be gratefully received!