Leadwork in Falkirk & Central Scotland

Sheet lead is sold by code, which is simply a measure of thickness. The higher the code, the thicker and heavier the sheet, and each code is colour-coded on the roll so there is no excuse for guessing. Using a code that is too thin is the single most common reason a piece of leadwork fails early.

• Code 3 (about 1.3mm). Light work only — soakers, small vertical cladding details. Too thin for anything exposed to water running over it.
• Code 4 (about 1.8mm). The standard for most domestic flashings: chimney aprons, stepped and cover flashings, soakers, small vertical faces. This is what belongs on the majority of Falkirk houses.
• Code 5 (about 2.2mm). Valleys, back gutters, dormer cheeks and small flat areas such as a porch roof. Anywhere water sits or concentrates.
• Code 6 (about 2.6mm). Larger valleys, parapet and box gutters, bay roofs, and exposed positions where a thinner sheet would fatigue.
• Code 7 and 8 (about 3.2mm and 3.5mm). Heavy-duty work: large flat lead roofs, church and hall roofs, and anywhere the lead is walked on.

Thickness is only half of it. Lead moves a surprising amount with temperature, so individual pieces have to stay short — around 1.5 metres for a flashing, with a lap or welt at every joint, and bay sizes rising with the code. A single eight-metre strip down a valley will split whatever the code, because it has nowhere to go. We tell you the code and the piece sizes we are using, and you can ask any roofer for the same.

Properly detailed lead outlives the roof around it. When it goes early, the cause is almost always one of these.

1. Thermal fatigue. Pieces cut too long cannot move freely, so the movement concentrates at one line and work-hardens the metal until it cracks. You see a straight split, often with a rippled surface either side — the classic 1960s and 1970s failure.
2. Undersized code. Code 3 or 4 used in a valley or a back gutter that should have been code 5 or 6. It tears at the fixings and dishes between supports.
3. Poor fixings and no chase. Flashing pushed into a joint without being chased in and wedged with lead clips, relying on mastic to hold it. The mastic perishes, the top edge lifts, and wind-driven rain runs behind it.
4. The sealant repair. Silicone, flashing tape or bituminous paint over a split. It buys a winter, traps water underneath, and makes the eventual proper repair more expensive because the lead has to be cleaned or replaced entirely.
5. Theft. Still a real problem on churches, halls, older public buildings and any flat lead roof reachable from a low wall.

Because most of these show up as a damp patch indoors rather than a visible fault on the roof, diagnosis matters. A stain beside a chimney breast is usually the back gutter; one several feet from any wall is usually a valley. Our guide to what lead flashing is and why it fails walks through the symptoms, and chimney repairs in Falkirk covers the stack itself, which is often due attention at the same time.

New lead reacts with rainwater and forms a white carbonate on the surface. Left alone it settles into the even grey patina everyone recognises, but for the first few months that residue washes off and runs down whatever is underneath. On a Falkirk house with roughcast or sandstone below the flashing, that means white streaking down the gable.

The fix is patination oil, brushed onto every exposed face on the day the lead is fitted, before it gets wet. It is a five-minute job and a fair test of whether the work was finished properly. If new lead is left untreated and the streaks appear, the lead is fine but your wall is not.

Then look at the shape of the work. Good lead is dressed to the surface it sits on, following the tile profile and the mortar courses without wrinkles, gaps or bruising, with steps up a chimney that follow the coursing and top edges chased into a joint and wedged rather than surface-fixed.

We fit lead because it works, not because it is traditional. It is not the answer to everything, so here is an honest comparison.

Lead is the right choice for chimneys, abutments, valleys, parapet gutters and any junction that must absorb movement and be dressed into an irregular surface. A well-detailed flashing should see out fifty years or more.

Lead-replacement flashings — the self-adhesive aluminium and butyl composite rolls — have a legitimate place. They are lighter, cheaper and of no interest to a thief, which suits an outbuilding or a roof with a theft history. They are not, in our experience, a fifty-year product, and they depend on an adhesive bond to a clean dry surface, which is optimistic on Scottish sandstone in February.

GRP and EPDM are flat-roofing materials, not flashing materials. Either suits a bay or porch roof if designed in from the start — see flat roofing in Falkirk — but neither replaces a dressed lead upstand into a wall.

Flashing tape and sealant are emergency measures. We use them to stop water while a proper repair is booked, and we say so on the invoice. Anyone selling tape as a permanent chimney repair is selling next year’s leak.

One category where lead is not optional: listed buildings and conservation areas. Falkirk Council’s planning team will expect like-for-like lead on a listed roof, and a modern composite can need consent you will not get. The same applies to traditional slate roofs where soakers were part of the original design — see slate roofing in Falkirk.

Metal theft has never gone away, and lead on a church, hall, school or older commercial building in the Falkirk area is still a target when scrap prices climb. It needs handling differently from a domestic flashing failure.

If lead has been stripped from a building you are responsible for, the order matters. Report it to Police Scotland on 101 and get a crime reference number, because no insurer will progress a claim without one. Photograph everything before it is touched. Then get the roof covered: the water damage over the following fortnight is usually worse than the value of the lead taken. We can make a stripped roof watertight and provide a report and dated photographs for the claim.

On the replacement, check your policy first. Many buildings policies now cap metal theft cover, exclude it after a first claim, or require forensic marking, alarms and roof-level signage to keep it. That is often the point at which a terne-coated stainless or composite alternative genuinely makes sense: almost no scrap value, so the roof stops being a target. On a listed building, agree that change with Falkirk Council before you commit.