Why Chimneys Cause So Many Roof Leaks
Chimneys are one of the most common sources of roof leaks on older properties in Birmingham. They project up through the roof covering and are exposed to weathering on all sides, making them vulnerable to deterioration over time. The problem is that chimney leaks are often slow and insidious — water trickles in gradually, travels down inside the wall and only becomes visible inside the property weeks or months after the initial failure.
By the time a chimney leak is noticed internally, significant damage can already have been done to timbers, plasterwork and insulation. This is why we always recommend getting a chimney inspected if you see even minor internal damp near a chimney breast — early intervention is far cheaper than allowing a slow leak to continue.
SB Margan Roofing deals with chimney and leadwork issues regularly across Birmingham. We diagnose the root cause of the problem rather than applying surface-level patches that will fail again within a season.
Lead Flashing
Lead flashing is the primary weatherproofing seal between your chimney stack and the surrounding roof tiles. It consists of lead sheets dressed into the mortar joints of the chimney and overlapping the adjacent tiles, forming a watertight barrier that accommodates the movement between the chimney and the roof structure.
Over time, lead flashings can fail in several ways: the lead may crack or split through metal fatigue; the mortar joints into which the lead is dressed may deteriorate allowing the flashing to lift; or previous bodged repairs using bitumen compounds or caulk may fail. We replace lead flashings using traditional methods — cutting and dressing new lead into properly raked mortar joints and pointing in with appropriate mortar. This is the correct, durable solution rather than painting over problems with sealant.
Chimney Pointing
The mortar joints between the bricks of a chimney stack are exposed to extreme weathering — rain, frost and thermal movement all take their toll. On older properties, the original mortar was typically a soft lime-based mix; when this is repointed using modern cement mortars (which are too hard and inflexible), further cracking often results. We use appropriate mortars for the age and construction of the chimney, ensuring the pointing lasts and doesn’t cause damage to the brickwork.
Failed pointing allows water into the brick itself. In winter, this water freezes, expands and causes spalling (the face of the brick breaking away). Left long enough, this can compromise the structural integrity of the stack. Repointing at the right time prevents this and significantly extends the life of the chimney.
Flaunching
The flaunching is the cement cap that surrounds the chimney pots, forming a weatherproof seal and holding the pots in position. Like pointing, flaunching is subject to cracking and deterioration over time. Cracked flaunching allows water to track down around the pot and into the chimney structure. We carry out full flaunching replacements and repairs, properly bonding new mortar to sound existing material where possible.
Chimney Stack Repairs
More extensive chimney stack repairs — replacing damaged brickwork, rebuilding sections of the stack, or replacing chimney pots — are all within our scope. We carry out chimney stack repairs at full height, working safely and efficiently to restore the stack to good condition.
Chimney Removal
Many homeowners with redundant chimneys — those not connected to any active fireplaces or appliances — choose to have them removed below roof level to eliminate ongoing maintenance and potential leak risks. We carry out chimney removals, lowering the stack below the roofline, installing a concrete raft capping at roof level, re-tiling over the area and making good the internal breast where required.
Chimney removal can also be the right option where a stack has deteriorated to the point where the cost of repairs would approach or exceed the cost of removal. We’ll advise honestly on this when we assess the chimney.
Chimney Cowls
Chimney cowls are fitted to the tops of chimney pots to prevent water ingress, reduce downdraught and stop birds from nesting. We supply and fit a range of cowl types including rotating cowls, anti-downdraught cowls, and capping cowls for decommissioned pots.
Frequently Asked Questions
How do I know if my chimney is leaking?
Common signs include damp or tide marks on the internal chimney breast wall, a musty smell in rooms with a chimney, staining on the ceiling near the chimney, or visible deterioration of the chimney stack when viewed from the ground (crumbling mortar, spalling bricks, displaced pots). If you see any of these, it’s worth getting the chimney inspected sooner rather than later.
Can chimney leaks be repaired without scaffolding?
Minor flashing repairs can sometimes be carried out from the roof itself using ladder access. For more extensive work, particularly on taller properties or chimneys that require all-round access, a scaffold or cherry picker may be necessary for safe working. We’ll discuss this during the survey and factor any access costs into your quote.
Should I repair or remove my chimney?
This depends on the condition of the stack, whether it’s attached to an active fireplace or appliance, and your preferences. A well-maintained chimney adds character to a period property. However, if the stack is in poor condition and not in use, removal can be a cost-effective long-term solution that eliminates future maintenance. We’ll give you an honest assessment and the costs of both options.
Is chimney pointing covered by home insurance?
Chimney repairs resulting from storm damage may be covered by buildings insurance. Gradual deterioration through weathering is generally considered wear and tear and is not covered. It’s worth checking your policy and, if in doubt, we can provide a detailed report and quote to support an insurance claim.