Understanding Chimneys
- Tollington Surveyors
- Jun 18
- 2 min read
Understanding Chimneys
Many Victorian and Edwardian homes across North London — in areas like Muswell Hill, Islington, Crouch End, Finsbury Park and Tottenham — still have their original chimney stacks and breasts. These features once played a vital role when open fires were the main source of heating. With modern central heating, most chimneys now stand unused but still need proper care.
What were chimneys for?
Traditionally, chimneys allowed smoke and gases from fireplaces to vent safely outside. Today, open fires are rarely used — most homeowners prefer the extra space of a square room rather than keeping a bulky chimney breast.
Should I keep mine?
If you are carrying out major renovations, removing an unused chimney breast can free up valuable space. However, in Conservation Areas or on listed buildings, removing a chimney stack is more complicated and usually needs planning consent.
Why vent and cap?
If you keep your chimney:
Vent the chimney breast internally to prevent damp and condensation building up inside the flue.
Cap the chimney pot at roof level to stop rain, debris and birds getting in.
Keep the flue ventilated and dry — blocked or sealed chimneys trap moisture, which can cause damp patches on internal walls.
Thinking of using your chimney again?
If you plan to reopen a fireplace, always get the flue tested and swept by a HETAS registered chimney sweep to make sure it’s safe.
Other key points to check
Flauching: This is the mortar at the base of the chimney pots. It seals them and sheds rainwater. Over time, flauching cracks and lets water into the stack — check for damage regularly.
Rendered stacks: Rendering hides the brickwork. It can help protect against weather but also conceals cracks and loose bricks. Look for bulging or blown render — it might be hiding a bigger problem.
Parapet walls: These are short walls that rise above the roof edges. They should have a coping stone, half-round tile or hip tile to stop water soaking in. Damaged mortar joints can let water in and cause leaks and timber decay.
Routine care
Vent unused chimneys at low level.
Cap chimney pots to keep out rain and birds.
Inspect flauching and render for cracks.
Check parapet walls and ensure copings are sound.
Include chimneys and parapet walls in your annual maintenance checks.
Drone surveys are a good way to get a closer look where ladders can’t reach — we always do our best from ground level, but drones add an extra layer of detail.
Chimney stacks are an important part of older homes and, if not looked after, can lead to bigger problems over time. We understand how they work and what to watch for.
If you own or are buying a home in Muswell Hill, Islington, Crouch End, Finsbury Park or Tottenham and need a RICS Level 2 HomeBuyer Survey or a RICS Level 3 Building Survey, feel free to contact us. We’re always here to help you understand your property properly — chimney and all.
Tollington Surveyors is a small, locally-focused surveying company based in Stroud Green, and dedicated to serving the Haringey area. Learn more >
