Lead

Lead is a dense, soft, highly malleable and corrosion-resistant metal used in architecture since antiquity for roofing, flashing, gutters, downpipes and as a weatherproof seal around window glazing and stonework joints. Its extreme malleability allows it to be dressed by hand into complex flashing details around chimneys, dormers and roof penetrations that few other roofing metals can match, and its natural resistance to atmospheric corrosion has given lead roofing on historic European cathedrals and civic buildings a service life measured in centuries. Its use has declined since the mid-twentieth century because of recognized health hazards from lead exposure, particularly to workers handling it, though sheet lead remains in specialist use for flashing and heritage roof conservation where its working properties are difficult to substitute.