Is lead roofing safe to live under?

Lead sheet lays on the outside of a building, behind a barrier of slates, tiles and boards, and it is not in the air you breathe or the water that comes out of your taps. As the metal weathers, a thin, stable oxide and carbonate layer forms on the surface, the dull grey that gives old lead its look. That layer protects the metal underneath and is one reason lead lasts so long.

In everyday life, a householder with lead flashing at the chimney has little reason to worry. Occupants are not exposed to a sound, weathered roof covering in the way a person cutting or melting the metal would be. The metal is fixed and covered, and nobody is handling it. The risk changes when the sheet is disturbed, removed, cut, burnt or melted.

If you are concerned about a particular roof, mention it at survey and we will describe what is there. A look at the leadwork explained guide shows where lead is used on a typical house.

Lead enters the body mostly through hand-to-mouth contact and by breathing fine dust or fume. Good habits cut that risk sharply. People who work with lead keep food and drink away from the work area, wash their hands and face before eating or smoking, change out of dirty work clothes and keep them away from children.

Cutting lead sheet with a knife creates little dust. Grinding a chase in old mortar creates a lot of dust, so a guard with extraction and a mask suited to the dust are standard. Old painted lead flashing, or lead mixed with old paint on timber beneath it, can release fine particles when scraped or sanded, so those jobs call for care.

Lead should never be heated with a naked flame without proper training, because the fumes are harmful. Welding or lead-burning is a specialist task. For how that process works, see lead welding.

Rain falling on lead can carry traces of dissolved metal and a pale deposit. On stone, you may see a white stain below a lead flashing. This is not dangerous to touch, though it is better washed away than left to build up.

For rainwater harvesting, lead is the reason for a simple rule: use water from a roof that has lead on it for watering plants and cleaning, not for drinking, cooking or filling a paddling pool. Our page on a water butt on a downpipe describes the fitting itself. If you grow vegetables, consider the source of any water you store, and rinse produce before eating it. A butt fed from a roof with no lead is a simple alternative if you want to use the water on edible crops.

Offcuts and old lead removed from a roof are valuable and attract thieves. They also belong with a scrap metal recycler, not in a household bin or left lying around. When we strip old lead, it leaves the site with us.

The risk from the metal does not vary much with the code, but the work does. Thin soakers and light flashings are quick to fit and generate small offcuts. Thick sheet used in gutters and flat roofs is cut and bossed in larger pieces, which means more time in contact with the metal, so hygiene on site matters more on those jobs. Pitched roofs with many small lead soakers behind slates mean a lot of small pieces handled by hand.

For the right thickness in each place, the pages on the lead code for flashing and the wider lead codes guide explain how a roofer chooses. Soakers, the small folded sheets that sit between slates at a wall, are covered under lead soakers.

Why a sheet cracks is a different safety question, since a cracked sheet leaks into the building and may need to be replaced. See why lead cracks for causes.

Do not strip, burn or sand old lead yourself. Painted lead in particular can hold old paint layers that release dust when disturbed, and the combination is better left to people with the right extraction and protective kit. Keep children and pets clear of the ground below any roof where work is going on, and ask the roofer how offcuts and dust will be cleared. Close windows facing the work and bring in washing.

Afterwards, wipe down any surface near the work with a damp cloth rather than sweeping, which lifts dust into the air. Wash clothes worn near the work separately from the family wash, and keep a pair of shoes for the garden path that you leave at the door.

If someone in the household is pregnant, or there are very young children, mention it before work begins, so the plan can allow for more careful tidying. If you have specific health worries, ask your GP, who can advise on lead exposure. A roofer is not the right person to judge a medical question, and we would sooner you asked a doctor than relied on our word.

After a job, we clear the site and remove all waste, including cut ends and dust. Before work starts you have survey photographs and a written quote, and once it is done the workmanship is covered for 10 years, in writing. For more on what we do with the metal, visit lead roofing.