Leadwork is the part of roofing that deals with junctions. Tiles and slates cover the open slopes well enough, but a roof is full of places where the covering stops: where a chimney rises through it, where it meets a wall, where two slopes join in a valley, where a dormer window sticks out or a bay window sits below. At each of these, water has to be guided across the break, and lead sheet is the traditional and still often the best material for the job. Leadwork is both the material and the skill of using it. A leadworker shapes metal by hand, on the roof, to fit a particular place, and the quality of that shaping decides whether the junction stays dry for decades or leaks within a few winters.
Why lead
Lead has been used on roofs for a very long time because it has a rare set of properties. It is soft enough to be beaten into corners and over mouldings without tearing. It is heavy, so it stays put in the wind without elaborate fixing. It forms a grey oxide skin that protects the metal beneath, so it does not need painting. It resists most of the acids found in rainwater. And it is workable with simple tools, in the open, with no special equipment. The drawbacks are its weight, its cost, its attractiveness to thieves and the skill needed to work it. Where those drawbacks matter, alternatives exist, and we compare them in our guide to lead alternatives.
Modern roofing lead is milled: it is rolled in a factory into sheets and coils of an even thickness, made to a British and European standard. The thickness is given as a code, from 3 to 8, and each code suits particular jobs. Our guide to lead codes explains the system.
What leadwork covers
A roofer uses lead in a handful of recurring details. Each has its own name, and it helps to know them when you read a survey or a quote.
- Flashings. Strips of lead that seal the junction between a roof and a vertical surface. They include aprons across the front of a chimney, stepped flashings up the sides and cover flashings along walls.
- Soakers. Small pieces under tiles or slates beside a wall, which carry water out onto the covering. See soakers and step flashing.
- Back gutters. Channels behind a chimney that carry water round it.
- Valleys. Linings in the angle where two slopes meet. See what a lead valley is.
- Gutters and parapets. Lead-lined channels behind low walls, common on older houses.
- Flat roofs and bays. Sheet laid over a timber deck, with joints formed as rolls or drips. See bay roofs and canopies.
- Hips and ridges. Rolled lead capping on some roofs.
- Dormer cheeks. Sheet that clads the sides of a dormer window.
- Saddles and slates. Pieces that cover a hip or ridge junction, or a pipe or vent passing through the covering.
How lead is shaped and fixed
The tools of leadwork look unlike those of other trades. A dresser is a hardwood or plastic tool used to beat the lead flat against a surface. A bossing mallet and bossing stick coax the metal into curves and corners by stretching and gathering it, a technique called bossing. A lead knife cuts the sheet, and a hook knife trims. A chasing wedge is used to rake out the mortar joint, and lead wedges fix the top edge of a flashing into it.
The way a piece is held in place is as important as its shape. A flashing's top edge is turned into a chase and held with wedges of lead, then pointed in mortar, so the metal is mechanically locked, not just stuck on. Its lower edge is dressed over the roof covering and held with clips so the wind cannot lift it. Because lead expands and contracts with temperature, long pieces are broken into short lengths, with laps and rolls that allow movement. A piece that is too tightly fixed or too long will tear at the fixings over time. Where two pieces of sheet need to be joined without a lap, a leadworker can weld them with a lead-burning torch, giving a seam that is the same metal as the sheet.
Where you see leadwork on a house
Look at a typical house and you will find it in several places: round the chimney, along the line where a porch or extension roof meets the main wall, in the valleys between roof slopes, around a dormer window, over a bay window or a front door canopy, and at the edge of a roof where it meets a neighbour's wall. On older houses, it also lines hidden gutters. On modern houses, some of these details use lead-free materials, such as GRP valleys on concrete tile roofs, but chimneys and wall abutments still tend to be lead. The mix of lead and other materials depends on the age of the house, its covering and the preference of the original builder.
| Where | What the lead does | What goes wrong |
|---|---|---|
| Chimney | Seals the stack and carries water round it | Cracks, lifted edges, failed pointing |
| Wall abutment | Joins roof to wall with soakers and steps | Short soakers, loose steps |
| Valley | Channels water from two slopes | Fatigue at laps, debris, thin spots |
| Bay or canopy | Covers a small roof with many joints | Cracks at hips, rot beneath |
| Dormer cheeks | Clads the sides, seals the junction | Sheet too long, torn fixings |
How a leadworker approaches a job
A good leadworker starts by looking, not cutting. They study the junction: the direction of the water, the condition of the wall and chase, the profile of the covering and the movement they can expect. They measure up, then make a template from building paper or thin lead, because a flashing that follows an uneven wall must be cut to fit that wall. Only then is the sheet cut, bossed into shape and offered up. The piece is checked for fit, then dressed, fixed, wedged and pointed.
Order of work matters too. Soakers go in as the covering is laid. Back gutters and aprons are formed before the stepped flashings that overlap them. Valley linings go in before the tiles beside them. Getting the sequence wrong means laps run the wrong way, and water runs into the join rather than out of it. That is why leadwork on a re-roof is done in step with the tilers, not afterwards by someone who has never seen what went under the tiles.
Leadwork on modern houses
It is easy to think of leadwork as a period craft, but modern houses use plenty of it. Estate houses built from the 1960s onwards usually have lead at their chimneys, over bay windows and along party walls, with soakers or preformed trims where the roof meets a wall. Extensions add further abutments. The difference is that modern houses are more likely to have factory-made trims and lead-free alternatives in the hidden places, with lead kept for the visible and awkward details. A modern leadworker has to be comfortable with both worlds and judge which suits each detail.
How long leadwork lasts
Done well, leadwork can last a very long time, often as long as the roof covering around it. When it fails early, the cause is usually specification or workmanship: the wrong code, pieces that are too long, a loose top edge or sealant used in place of a proper fix. We explain the factors in our page on how long lead flashing lasts, and the symptoms of ageing in signs of failing lead flashing.
Lead and safety
People sometimes ask whether lead on a roof is a health risk. Lead sheet laid on a roof is stable, and the oxide layer that forms on it is not readily washed away in normal conditions. The risks are in handling and in dust or fume produced when lead is cut, burned or worked, which is why leadworkers wash their hands, avoid eating while working and keep offcuts and dust contained. We cover the subject in more detail in our answer on whether lead flashing is dangerous. Old lead is not thrown away: it is collected and recycled, as our page on what happens to old roof lead describes.
Leadwork and the rules
For most houses, new or replacement leadwork does not raise special rules beyond those for the roof as a whole. On listed buildings and in conservation areas, materials and methods can matter a great deal, and consent may be needed for changes. We cover that in our guide to leadwork on period and listed homes. Where re-roofing work is large enough to be notifiable under the Building Regulations, we deal with that side.
What it costs, broadly
Costs depend on the details, access and the code of lead. For rough orientation, a four-sided chimney flashing is quoted in UK cost guides at around £525 without scaffold and nearer £1,000 with it. Those figures come from third-party guides and are no guide to what any particular job will cost; the price you are given is fixed only after the survey. Our page on lead flashing replacement cost looks at the drivers in more detail.
What we do
We handle leadwork on houses and small commercial buildings around Basingstoke, from a single chimney to a full set of bay roofs and dormer cheeks. Every job starts with a survey and photographs of the lead as it is, followed by a written quote at a fixed price. Where a repair holds, we say so. The guarantee on our work is ten years, in writing. Our Basingstoke lead roofing service brings all of this together, and the first step is a call to 01256 213956 or a message through WhatsApp. If you are unsure which lead detail is failing on your roof, a photograph sent in advance helps.
