The short answer
Lead is toxic if it is swallowed or breathed in, but a flashing sitting on a roof is not a danger to the people in the house. The risk is during work: cutting, rubbing down, heating, or stripping old paint and corrosion creates dust and fume, and handling lead then eating or smoking with unwashed hands carries it into the body. Good hygiene and the right methods keep the risk low. Children and pregnant women should stay away from the work area.
Lead on a finished roof
Once fitted, a lead flashing, valley or covering is a stable layer of metal with a protective film of lead carbonate on the surface. It does not shed dust into the house, and the people living below are not exposed by its presence. The thing to bear in mind is rainwater. Run-off from a lead roof carries small amounts of the metal, so it is not a source to use for drinking water or for edible garden plants. Gutters and downpipes that take that water should discharge into the normal drainage system. Our guide on whether roofers still use lead puts the material in context.
Where the real risks arise
The danger comes when lead is disturbed. Lead enters the body in three ways: by breathing in dust or fume, by swallowing particles, and, to a much smaller extent, through contact. Roofers cut lead with shears and knives, which makes little dust. Cutting a chase into brickwork to receive a flashing, on the other hand, raises dust from mortar and from the old lead and paint, and rubbing down or burning off old lead-based paint creates fine particles. Lead welding, which uses a gas flame, produces fume if the metal overheats. Lead dust in the loft from old flashings is also a hazard. Dirty hands are the most common route: someone handles lead, then eats a sandwich or smokes without washing.
The Health and Safety Executive publishes guidance on working with lead and on the duties of an employer where lead exposure is possible; you can find it at hse.gov.uk. Employers have to assess the risk and put controls in place, and workers should be told what they are.
Simple precautions that work
On a roofing job, the sensible habits are plain. Wash hands and face thoroughly before eating, drinking or smoking, and do not eat on the roof or in the work area. Keep work clothes separate and wash them away from family laundry. Use water or extraction when cutting into masonry, and wear a suitable mask where dust is made. Clear offcuts and dust before leaving site, and do not sweep dry. Do not burn old lead or heat it beyond what the job needs. Good housekeeping on the roof and in the garden, with a sheet or tray to catch offcuts, keeps the problem where it belongs.
People who live in the house should keep out of the area while work goes on, and pets and toddlers who put things in their mouths should be kept well clear of cut lead and dusty surfaces until it has been cleaned up. Pregnant women and young children are the most sensitive to lead, and are best kept away from the work altogether.
Old lead and waste
Offcuts and old lead have a scrap value and a use, and the metal is recycled, not thrown into a skip. Our page on what happens to old roof lead explains where it goes. Old lead paint on fascias, windows and bargeboards is a different matter and needs care when it is rubbed down; if you suspect it, ask the roofer how they deal with it before work starts.
If you find lead dust at home
Old flashings sometimes leave a grey deposit on the sill, the loft floor or the wall below. Do not dry-sweep or vacuum it with an ordinary cleaner, which blows the finest particles into the air. Damp-wipe the surface with disposable cloths, bag them and wash your hands. If young children live in the house, take extra care to clean floors and window sills where they play. Anyone who worries about exposure can ask their GP about a blood lead test, and the Health and Safety Executive guidance covers what employers must do for workers. If the deposit seems heavy or the source is unclear, a roofer can check whether it comes from a failing flashing, a lead paint finish or something else.
Other hazards worth knowing about
On an older roof, the larger risk may not be the lead at all. Asbestos cement sheets on garages and outbuildings, and old insulation materials, need handling by trained people. Falls are a bigger danger than lead on any roof. A roofer who works carefully on all of these is the one to choose; if you are choosing someone for the work, the page on questions to put to a roofer is a good start.
We keep the working area tidy, wash and clear up before leaving, and take the old lead and waste away with us. For leadwork, begin at the lead roofing and leadwork hub, the homepage, or ring 01256 213956.
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