Chimney Breast Leak in South West London

Name: Chimney Breast Leak Repair
Brand: Knights Roofing
Price: from 49 GBP
Availability: InStock

Chimney Breast Leak – All Work Guaranteed. Battersea Power Station The Engine Room London

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Chimneys

A chimney breast leak is one of the most distressing problems London homeowners face because it manifests as visible water damage inside your home. Unlike external chimney issues that you might spot during a roof inspection, chimney breast leaks appear as damp patches, brown staining, peeling wallpaper, or crumbling plaster on the internal walls surrounding your fireplace or chimney structure. These internal leaks require immediate professional attention because they indicate water has already penetrated deep into your property's structure.

At Knights Roofing, we've diagnosed and repaired hundreds of chimney breast leaks across London properties over the past 20 years. Our specialist team understands that internal chimney breast leaks rarely originate from the breast itself. Instead, they typically result from failed flashing, deteriorated pointing, or compromised weatherproofing on the external chimney stack. Water enters through these external failures, travels through the brickwork and internal cavity, and eventually appears as dampness on your interior walls—often several feet below the actual point of water entry.

Based in Battersea, our certified chimney repair specialists serve homeowners throughout London, from period properties in Kensington and Richmond to Victorian terraces in Hammersmith and Fulham. We provide emergency chimney breast leak repairs, comprehensive diagnostic surveys, and permanent waterproofing solutions that address the root cause rather than just treating the symptoms. Read more here about why chimney mainenance is so important.

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chimney breast leak, chimney crown leak, chimney flashing leak, chimney leaking repair, chimney leaning

breast leak fixed - the result of our work

Symptoms of a Chimney Breast Leak

How to Spot a Chimney Breast Leak

Brown stains on internal walls – often appearing around the fireplace or chimney breast.
Peeling wallpaper or paint – caused by persistent moisture.
Damp patches or plaster bubbling – a sign water has penetrated deep into the wall.
Musty or mouldy smells – moisture encourages mould growth inside walls.
Water dripping or damp spots – sometimes visible on ceilings or near the chimney breast.
Flaking plaster or crumbling masonry – long-term leaks can damage the internal structure.
Cold or damp feeling walls – affected walls often feel cooler due to trapped moisture.

Early recognition helps prevent serious structural damage and costly repairs.

Common Chimney Issues

Spalling Bricks

Spalling bricks occur when moisture seeps in the bricks and mortar, resulting in the bricks breaking apart. Should you notice spalling bricks within your chimney, it is of utmost importance to contact a professional to prevent any additional damage.

Leaning Chimney Pots

Leaning chimney pots are not just a charming architectural quirk. They can also be a sign of potential danger, as their instability could lead to them toppling over, damaging roofs, cars, or even injuring people below. Regular maintenance and inspections are necessary to ensure that these old structures remain safe and secure.

Flashing Damage - The Primary Cause of Chimney Breast Leaks

The flashing refers to the protective layer of material which seals the junction between your chimney stack and the roof surface. Lead flashing deterioration causes approximately 60-70% of all chimney breast leaks we repair in London. When flashing fails through cracking, tearing, or separation from the brickwork, rainwater flows directly down the external chimney face and penetrates into the structure. This water travels through the brickwork and appears as internal dampness on your chimney breast walls.

Flashing failure occurs due to thermal expansion and contraction, building movement, poor initial installation, or simply age. Victorian and Edwardian properties particularly suffer from original lead flashing that has reached the end of its service life. If you notice damp patches on your chimney breast walls, failed flashing is the most likely culprit and requires immediate professional repair to prevent extensive internal damage.

Our Chimney Breast Leak Repair Process

Step 1: Comprehensive Inspection
We conduct a full internal and external survey of your chimney to locate the source of the leak. Moisture tracing and visual inspection identify whether flashing, brickwork, or pointing is compromised.

Step 2: External Chimney Assessment
We examine the chimney stack, lead flashing, and pointing for signs of wear, cracks, or deterioration.

Step 3: Flashing & Masonry Repairs
Repair or replace damaged flashing, repoint bricks, and restore waterproofing to prevent further water ingress.

Step 4: Internal Remediation
Treat internal damp, repair plaster or paint damage, and ensure walls are fully dry and restored.

Step 5: Final Quality Check & Aftercare
We verify that all leaks are resolved and provide recommendations for maintenance to prevent recurrence.

Why Choose Our Chimney Services?

Knights Roofing knows the importance of maintaining your property's health and safety. That's precisely why we provide an extensive chimney repair solution aimed at ensuring your chimney remains in optimal condition. Our company also has valid certificates FSC and PEFC.

While chimney breast leaks typically originate from failed flashing or deteriorated pointing, damage to the chimney crown at the very top of your stack can also cause internal moisture problems. If you've noticed cracks or deterioration on the concrete cap covering your chimney top, our specialist chimney crown repair service addresses these external problems before they lead to serious internal damage. Crown leaks allow water to pour directly into the chimney structure from above, eventually causing the same internal dampness symptoms as breast leaks.

Professional service repairing our roof, good value, would recommend.

Mr Bennett, Wimbledon

Complete chimney repointing and roof repair at our property to a very high Standard.

Mr and Mrs Howe, Clapham

Repaired our lead flashing and completed maintenance work to our leaking roof, great job.

Daniel, Richmond

Frequently Asked Questions

What causes a chimney breast leak?

A chimney breast leak is most commonly caused by failed flashing, deteriorated mortar pointing, porous brickwork, or damaged weatherproofing on the external chimney stack. Water enters from the outside, travels through the brickwork, and appears internally as damp patches, staining, flaking paint, or crumbling plaster. Immediate repair helps prevent structural damage to the internal wall.

How do I know if my chimney breast needs repair?

Signs include brown stains, flaking paint, damp patches around the fireplace, musty smells, bubbling plaster, or visible moisture on the chimney breast wall. In many cases, the actual leak point is on the external chimney—not the breast itself—so a professional inspection is essential.

What is chimney flashing, and why is it important?

Chimney flashing is the watertight seal between the chimney stack and the roof. When flashing cracks, lifts, or separates from the brickwork, rainwater runs down the chimney and causes internal chimney breast leaks. Failed flashing is responsible for 60–70% of the chimney breast leak repairs we complete in London.

Can a leaning chimney pot be dangerous?

Yes. A leaning chimney pot can allow water ingress, reduce stability during storms, and pose a risk of collapse. It should be inspected and secured or reset as soon as possible to prevent leaks and safety hazards.

What are spalling bricks, and should I be worried?

Spalling bricks occur when moisture freezes and expands inside the brick, causing the surface to flake or crumble. Left untreated, this allows more water into the chimney, leading to deeper structural issues and internal leaks. Early repair prevents costly reconstruction work.

Do you offer chimney breast leak repairs across London?

Yes. Based in Battersea, we repair chimney breast leaks across all London areas, including Kensington, Richmond, Hammersmith, Fulham, Chiswick, Putney, and surrounding boroughs.

How much does chimney breast leak repair cost?

Costs vary depending on the root cause—flashing repair, repointing, brick replacement, or full weatherproofing. Most chimney breast leak repairs in London range from £250–£950, but complex structural issues may cost more. We provide fixed, transparent quotations after an on-site survey.

Can chimney issues cause internal damp?

Absolutely. Most “internal damp” around chimney breasts is caused by external water ingress—usually through failed flashing, mortar decay, or porous bricks. Addressing the source of the leak resolves internal damp more effectively than treating surface symptoms.