Leadwork & flashing · A focused guide
How is the hidden roof junction behind a chimney assessed?
Published by Big Ben Roofing Ltd
The upper roof junction behind a chimney may be concealed from a ground-level view, so an intact-looking front apron does not establish the condition of the whole detail. Describe which parts are visible and where any internal stain appears. Ask whether the assessment includes the back gutter or other upper junction, the adjoining covering and its drainage route. Closer access should be planned by the contractor rather than attempted for enquiry photographs.
Locate the stack within the roof
Say whether the chimney stands near the ridge, partway down a slope or beside another roof section. Existing photographs from earlier work can help identify the hidden area. Record any recent patching and whether it concerned the front, sides or upper junction. This prevents a description of chimney flashing from being mistaken for evidence that every side has already been inspected.
Define access and connected covering work
If the upper junction requires opening, ask which tiles or slates will be lifted and whether the lining and support can then be examined. The proposal should distinguish clearance, a local repair and renewal of the detail. Confirm how the water route past the stack will be addressed and how findings at concealed adjoining areas will be documented before extra work proceeds.
Useful details to record
- Identify the stack position and the sides visible from the ground.
- Share earlier chimney-junction photographs if already available in your records.
- Mention which sides were included in any previous flashing repair.
- Ask whether the hidden upper junction and discharge route are assessed.
Use information already available from indoors or ground level. Do not climb onto the roof or disturb materials to complete this checklist.
Can a front-only chimney flashing repair stop a leak from behind the stack?
It depends on the identified water entry point. A repair to the front should not be assumed to address a separate upper junction. Ask which finding supports the proposed location and which chimney sides remain outside the scope.
Background reading
- Lead Sheet Training Academy: flashing and junction details
- SPAB: maintaining slate, tile and metal roofs
General guidance helps frame the questions. The cause, suitable materials and scope depend on inspection of the particular roof.
Related questions
Does a chimney leak need flashing work or repairs to the stack?
Separate the chimney-to-roof junction from the masonry and upper stack when defining an assessment and repair proposal.
Does a leaking lead valley need clearance or lining repair?
Separate a debris observation from evidence of damaged valley lining and define what an inspection or repair proposal should include.
Discuss what you have noticed
Include your postcode, the affected roof section and when the concern appears. The team will review the enquiry and confirm the next step, scope and availability.
Request a roofing assessment