Roof chimney in Auderghem
We repair and renovate roof chimneys in Auderghem and the neighbouring communes. Repointing, chimney pot replacement, flue lining, loose flashing: these are frequent interventions on the houses of Auderghem, especially on older buildings whose chimneys haven't been touched in 20 or 30 years. A damaged chimney doesn't just put the roof at risk; it can also create a carbon monoxide hazard if the flue is failing.
What does this work involve
The roof chimney is a masonry structure passing through the covering. It has several elements, each of which can call for a different intervention.
The flashing: the piece of zinc work (usually zinc or lead) joining the base of the chimney to the tiles or slates. When the flashing comes loose or cracks, water seeps straight into the structure. It's the most common cause of chimney-related leaks.
Repointing: the mortar joints between the chimney's bricks degrade over time. Cracked or loose joints let water into the flue and the wall structure.
The chimney pot: the ceramic or concrete cap crowning the flue. A broken or missing pot lets rain straight into the flue.
Flue lining: fitting a stainless steel or steel tube inside the existing flue. It rehabilitates a damaged flue, adapts the diameter to a new heating appliance, or guarantees the flue's tightness. It's often required when installing a stove or boiler.
When should you act
A few situations that deserve a look:
- Damp traces appear on the interior wall around the chimney or on the nearby ceiling
- Water gets into the fireplace when it rains
- You notice bricks crumbling on the chimney stack from the street
- The mortar between the bricks is fragmented or missing
- You're installing a new stove or boiler and the chimney sweep flags the flue as inadequate
Why it happens
Chimneys go through the same freeze-thaw cycles as the rest of the roof, but suffer more because they're vertical and directly battered by rain and wind. Pointing mortar is porous: it absorbs water, freezes, expands and eventually cracks.
On the houses of Auderghem built between 1930 and 1970, the original flashings are often lead or mortar. Lead lasts a long time but eventually cracks after several decades. Mortar lasts far less: 10 to 15 years in Brussels conditions.
A chimney that's no longer used is sometimes neglected — wrongly. The open flue lets water in. A broken or missing pot can be enough to cause regular water ingress into the house.
What makes the price vary
The overall state of the chimney is the first factor: a simple repointing is a short intervention, a complete zinc flashing replacement with the slates rebuilt around it takes more time. The height of the stack above the roof matters: the higher it is, the trickier the access.
The flashing material (zinc, lead, galvanised steel) affects cost and durability. And if a flue lining is needed, the diameter and length of the flue count. In some cases, the chimney intervention is combined with a more general roof repair: we do both during the same climb, which avoids an extra call-out.
See also: Roof repair · Zinc work
Frequently asked questions
My chimney flashing leaks: does the whole chimney need redoing?
Not necessarily. If the stack is still sound and only the waterproof junction is failing, redoing the flashing is enough. It's cheaper than redoing everything and just as effective if the masonry is in good condition.
Is flue lining mandatory for a wood stove?
Not always legally, but in practice a chimney sweep or installer will often ask about the state of the flue. If it's cracked, too wide for the stove, or in poor condition, lining will be necessary for safety and efficiency. Better to do it before the sweep demands it after the first inspection.
Can a chimney we no longer use be sealed off?
Yes, but leaving minimal ventilation to avoid condensation in the flue. We can advise the best approach depending on the type of chimney.
Do you also check the structure around the chimney?
Yes, we look at the state of the nearby timber while we're up there. If we see moisture traces or damaged wood, we flag it.
Is your work guaranteed?
Yes, a 10-year workmanship guarantee. For a flue lining, the product warranty comes on top, depending on the manufacturer.