The short answer
A lead flat roof can usually be patched when the damage is local: a split, a pinhole or a lifted seam in otherwise sound sheet. Repairs are made by fusing the split with a flame or by letting in a new piece. If cracking is widespread, or the deck beneath is soft, renewing the affected bay is the better value.
Why lead is easier to mend than most flat roofs
A lead flat roof is not one membrane. It is a set of separate sheets laid in bays, with rolls running down the fall and drips across it. Each bay is a self-contained strip, so a fault in one does not condemn its neighbours. A felt or rubber roof is different: a failed seam can let water travel under the covering and appear far from the hole.
Lead is also malleable and can be worked on site. A cracked area can be trimmed out and a new patch bossed into place, or a split can be closed by melting its edges together. The repaired metal behaves like the original, which is why repair is a normal part of looking after lead rather than a stop-gap. The way the whole system works is explained in our guide to lead flat roofs on Stroud's period houses.
Less quotes 50 to 100 years for a lead flat roof, and MyBuilder's 2026 flat roof guide gives lead at £150 to £200 or more per m². A roof with that value in it is worth repairing carefully rather than replacing at the first leak.
Faults that suit a patch
Patching suits a fault whose cause is clear and confined. Typical cases are a split along a fold where the metal has fatigued, a pinhole worn by a stub of an old fixing, a lifted edge at a drip, or a tear from something dropped or a ladder footing. A burn or puncture from a previous trade is another.
The fix follows the fault. A small split may be closed by welding. A larger damaged area is cut out to a neat shape and replaced with a new piece joined at the edges. A lifted seam is re-dressed and re-secured. For scale, MyJobQuote prices a chimney flashing patch at £150 to £250, while MyBuilder lists roof repairs overall at £150 to £1,500 and minor ones at £100 to £300. Those are national figures. Ours follow the survey, in writing.
Check the cause before the crack
A repair that ignores the reason for the split will fail again. Lead cracks because it has been fixed too tightly, laid in bays that are too long, or stressed by a deck that moves. If the sheet has fractured in several places, welding each crack treats the symptom. We look for the pattern before agreeing that patching is worthwhile.
Signs that a bay needs renewing instead
There are limits to what patching can do. Whatever surrounds a repair must itself be healthy metal. Where the lead is thin from age, work-hardened and brittle, or cracked across its whole width, a patch simply moves the weak point a few centimetres. Several repairs on one bay is a signal that the bay is at the end of its time.
The deck matters as much as the metal. Soft or stained boards, sagging between joists, or a roof where water lies for days after rain mean the problem is below the lead. New lead on a bad deck repeats the damage. Putting that right calls for the covering to come up, the boards to be renewed and the falls corrected. IKO and Rockwool both describe the BS 6229 approach: design the deck at 1:40 so that tolerances still leave a finished fall of 1:80.
Renewing a single bay is often a middle path. The sound bays stay, the failed one is lifted, the deck is repaired and new lead is laid, with a roll or drip joining it to its neighbours.
How patching compares with replacing
The table sets out the decision as we see it on site. It is a guide, and the survey decides each case.
| Condition found | Usual route |
|---|---|
| One split or pinhole, sound lead around it | Weld or small patch |
| Lifted edge or loose seam | Re-dress and secure |
| Cracks across several folds | Renew the bay |
| Soft deck or standing water | Lift, repair deck, relay |
| Lead worn thin across the roof | Plan a full renewal |
If the roof is old, it helps to know what the lead is. A thinner, lower code laid long ago will not take repeated welding as well as a heavier sheet. Our answer on what lead welding is explains the technique and where it is a good choice, and where a mechanical repair is wiser.
Lead on a listed building is a further point. Repairing in the same metal is usually the gentlest course, though replacing a whole covering on a protected building should be raised with the council's conservation officer first.
A temporary fix while you decide
Active leaks get a different order of work: stop the water first, mend second. The stop-gap might be a sheet of membrane over the opening, described in the quote as a stop-gap before the lasting repair. It is worth having a proper look before the weather turns rather than relying on a patch of sealant. Our page on lead against zinc is useful if the leak has you wondering about a different metal altogether.
The survey photographs go to you alongside a written quote, and any repair is covered by a written 10-year guarantee on our workmanship. A phone picture sent by WhatsApp, a call to 01453 933613 or the enquiry form will start things off. The full range of leadwork we cover is on the lead roofing page.