Identify the lead detail and its job
Name the element before proposing a repair: flashing, soaker, valley, secret or parapet gutter, flat, capping, ridge, hip, outlet or another formed detail. Record its boundaries, falls, steps, laps, fixings and where collected water is expected to discharge.
An internal mark does not show which lead element failed. Follow the water route from catchment to outlet, including adjacent coverings and masonry. Mark staining, standing debris, displaced edges, open joints and overflow paths so the inspection distinguishes a drainage problem from failure of the sheet itself.
Diagnose movement, fatigue and previous repairs
Lead expands and contracts with changing conditions. Restricted movement, unsuitable sheet dimensions or fixing, wind lift and repeated stress can show as rippling, buckling, cracking or distortion. Punctures, corrosion, concentrated flow and failed surrounding details create different repair questions.
Record the location and direction of each defect and any earlier patches. A seal placed over a crack may hide the symptom without correcting movement or water concentration. Diagnosis should establish whether the sheet can still perform, whether a local repair is proportionate and what caused the failure.
Select lead code and sheet size for the detail
Lead codes describe sheet thickness and weight, but a higher code is not a universal solution. The detail, exposure, substrate, sheet dimensions, method of forming and required movement all influence specification. Avoid assigning an exact code from photographs or the building age alone.
The Engine Shed advises following detailed industry guidance for optimum sheet sizes and using suitable falls and steps where required. The repair record should therefore state the function, proposed code, maximum sheet layout, joints, clips and movement provisions for review before fabrication or installation.
Check compatibility with adjoining materials
Lead interfaces with slate, stone, mortar, timber, membranes, clips and other metals. Run-off, chemical contact, trapped moisture or an unsuitable underlay can affect performance. Specify separation, fixings and interfaces for the actual materials found rather than treating the lead as an isolated waterproof layer.
Inspect the support and adjacent fabric before renewal. Damaged sarking, open masonry, loose slate or a blocked outlet may need attention first. Mortar work beside lead should be sequenced so the sheet is protected and remains able to move after the surrounding detail is completed.
Choose repair, local renewal or wider renewal
A repair decision should consider the lead's overall condition, age only as context, the number and type of defects, design or installation faults and whether sound margins exist around a local failure. A temporary patch should be labelled and monitored as temporary rather than described as full renewal.
Local renewal may suit a discrete failed section where adjoining layout performs correctly. Wider renewal may be justified when sheet sizing, falls, movement or repeated defects are systemic. Set the decision boundary in the scope and identify any opening-up needed to confirm support or concealed interfaces.
Plan access, protection and work controls
Lead gutters and flats may occupy difficult high-level or concealed positions beside fragile slate and masonry. Define access around the inspection and repair questions, protect adjoining coverings and interiors, and maintain safe drainage or temporary protection while a detail is open.
The method should address removal, storage and recycling of replaced lead, weather constraints, any proposed hot work and protection of the substrate. These are site-specific planning matters, so an enquiry should not be treated as approval for a method before access and surrounding fabric have been assessed.
Record the specification and consent position
Photograph the existing layout, defects, edges and adjoining materials; add measured sketches where sheet divisions or falls matter. Record proposed code, sheet sizes, joints, fixing and clipping approach, underlay, interfaces and discharge. This creates evidence for review and future maintenance.
Changes to roofing leadwork may need planning-authority advice depending on the building, its location and the effect on character. Share known status, defect photographs, lead detail type, internal signs, access information and previous repairs when requesting an assessment, without assuming a code or repair method.
