A chimney passes through the roof and is exposed on all sides, so it combines masonry, mortar, pots, flaunching and lead weathering in one small but vulnerable area. A leak beside a chimney is therefore not automatically a flashing problem or a pointing problem; both need checking.
We repair external chimney stacks around Crawley where they interact with the roof, including repointing, leadwork, flaunching and local tile or slate details.
Where chimney leaks commonly start
Open mortar joints, cracked flaunching, loose pots, failed lead step flashing, front aprons and back gutters are all possible routes. Water can also soak through porous masonry and appear lower down the stack.
We inspect the stack above roof level and the junction with the covering so the repair addresses the whole weathered area.
Repointing a chimney stack
Sound repointing begins by removing failed mortar to an adequate depth without unnecessarily damaging the brick or stone. The replacement mortar needs to be compatible with the masonry and exposure.
On older buildings, an excessively hard cement-rich mortar can behave differently from softer historic brickwork, so material choice should respect the existing fabric.
Flaunching and chimney pots
The mortar bed around pots sheds water from the top of the stack and helps hold pots securely. Cracking, erosion and vegetation can allow water into the stack or leave pots unstable.
Where pots, cowls or flues are connected to active combustion appliances, roofing work may need coordination with an appropriate chimney or heating specialist.
Leadwork around the chimney
Chimney weathering commonly uses an apron at the front, stepped or cover flashing at the sides and a back gutter or similar detail on the high side. Each piece has to lap with the roof covering and allow for thermal movement.
Repeated sealant repairs around the front edge often indicate the underlying lead detail needs rebuilding rather than resealing.
Older and listed properties
Chimneys are important visual features on many older homes. Historic England encourages retention of original fabric and compatible repair where possible. Listed buildings can also require consent for alterations beyond ordinary repair.
Inspecting the stack from the top down
A chimney survey should connect the condition of the pots and flaunching with the brickwork and the roof junction below. Rain can enter at the top, travel within the stack and appear beside an otherwise sound apron flashing. We look for open joints, damaged brick faces, displaced pots and vegetation, then check the side flashings and the channel behind the stack. If a stack is leaning or has substantial cracking, masonry stability needs assessment before a weatherproofing repair is agreed. Pointing alone cannot correct movement or rebuild an unsafe chimney.
A repair that keeps the chimney and roof working together
The repair specification should identify the faces being repointed, any brick replacement and the separate lead details being renewed. Around a tiled roof, the side weathering must work with the tile courses; at the back, water needs a clear route around the stack. Access may involve scaffolding even when the visible defect is small. If the chimney serves a working fire or appliance, tell us before the visit so flue ventilation and any specialist checks can be coordinated. A cap chosen simply to keep rain out can be unsuitable for an active flue.
After the repair
Keep photographs of the finished stack and the agreed work description. Internal chimney staining may take time to dry, and old salts can remain visible after the external route of rainwater has been repaired. If damp continues, record whether it follows rainfall or cold weather. That distinction helps separate remaining weathering defects from condensation or another source of moisture.
Questions homeowners often ask
No. The leak may come from leadwork, flaunching, pots or the roof covering around the stack. We inspect all of those before specifying repair.
That is a structural and planning question as well as a roofing one. Removal can affect support, party walls, appearance and flues, so it needs separate assessment.
Possible causes include external weathering defects, condensation in a disused flue, salts in old masonry or plumbing elsewhere. The pattern needs investigation rather than assuming one cause.
Technical guidance and further reading
What affects the size and cost of the job?
Chimney, pointing and leadwork jobs are often small in area but detailed and access-sensitive. Height, scaffold requirements, the condition of masonry and the complexity of flashings or weatherings can matter more than the quantity of raw material.
- Height and safe access around the stack or abutment
- Condition of brick, stone and existing mortar
- Extent and type of existing leadwork
- Need to coordinate pointing, flaunching and roof-covering repairs
- Complex corners, back gutters, valleys or dormer details
- Requirement to match older or heritage materials
A quote you can actually compare
The scope should separate masonry repair from leadwork and roof-covering work so you can see what is actually being renewed. Where lead is replaced, the detail and area should be described rather than treated as an unspecified strip of metal.
We prefer defined scopes to vague allowances. If an important part of the roof cannot be confirmed until material is lifted, that uncertainty should be explained before work begins rather than appearing as a surprise at the end.
What we inspect and work on
Chimney repointing
Lead flashing and soakers
Loose pots and caps
Local tile repairs around stacks
Weathering and masonry checks
Related roofing services
More questions about this service
Can you fix the roof around a chimney without rebuilding it?
Often, yes. If the masonry is stable and the defect is limited to flashing, soakers or nearby tiles, a targeted roof repair may be enough. Rebuilding is considered where the condition of the stack itself makes a smaller intervention unsuitable.
Does repointing include the lead flashing?
Not automatically. They are separate parts of the job. We set out which mortar joints and which lead details are included, so you can compare the quotation and understand what will remain in place.