Lead flashing: when it fails and what it costs to fix
Lead flashing is what stops water entering at every roof junction — chimneys, parapets, valleys, bay windows and abutments. On most West London period stock the original lead is now 60–100 years old and the failure points are predictable.
How lead actually fails
Lead doesn't usually 'rot' — it splits. Decades of thermal movement cause hairline cracks along bends and dressed edges. Mortar pointing above the lead fails first, water tracks behind the flashing, and you see staining on the ceiling below long before the lead looks visibly bad from the ground.
Where we see lead failures most often
Chimney aprons and step-flashing on Edwardian terraces (Hampton Hill, Teddington, Twickenham), parapet flashings on Victorian villas (Wimbledon, Richmond, Hammersmith), bay-window roof lead on inter-war semis, and valley lead on hipped roofs across the TW and KT postcodes.
Repair vs full re-dress
Small splits and missing pointing can be patched with lead-burn welds and re-pointed. If multiple sections are cracked or the gauge is undersized, we strip and re-dress in Code 4–5 milled lead with proper steps, soakers and tingles. The cost difference is significant — we'll always show both options.
Why we don't use lead substitutes on period properties
Aluminium and synthetic flashing tapes are fine on modern utility roofs. On conservation-area or character properties they look wrong and most local planners discourage them. We default to Code 4 or 5 milled lead unless you specifically ask otherwise.
FAQs
Properly dressed Code 4–5 milled lead lasts 60–100+ years. Most early failures are due to undersized gauge, poor dressing technique, or unmaintained mortar pointing above the lead.
Often yes — hairline splits can be lead-welded and the mortar above re-pointed. We'll only quote a full re-dress if the existing lead is too far gone to be reliable.
Yes — most of our lead work is on conservation-sensitive properties in Hampton, Hampton Hill, Twickenham, Teddington, Richmond and Wimbledon. We default to like-for-like Code 4–5 milled lead.
Related reading
More on roof repairs and the jobs that usually come with it.
- Ridge tile replacement: mortar bedding vs dry-fix ridge
- GRP fibreglass flat roofs: pros, cons and when to choose them
- Missing or slipped tiles: how urgent is it really?Repairs & problems
- Chimney repointing and lead flashing costsCosts & budgeting
Looking for something specific? See our roofing services, cost guides, common roof problems or the areas we cover.
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