Chimney Repairs South Wales › Aberdare › Guide
Chimney stacks on Aberdare's Victorian and Edwardian terraces stand tall on a hillside that gets plenty of wind and rain. Over time the mortar fails and the brickwork starts to move. Here is how we decide between repair and rebuild, and what the rebuild involves from start to finish.
Why stacks lean or crack
Rain soaks the top of the stack more than any other part of the house. The mortar softens, frost opens the joints, and bricks begin to shift. Old flue gases also attack the inside of the brickwork, so one side often decays faster than the other.
That uneven decay is why stacks tend to tilt, usually away from the prevailing wind. A crack running up through several courses means the brickwork is no longer acting as one solid piece, and the stack is getting weaker the longer it is left.
What we check from the ground and loft
From the street we look at the lean against a straight edge, missing pots, and any bricks that have started to bulge or drop. In the loft we check for staining and damp on the chimney breast, and for any sign that the roof timbers around the stack have been wet for a while. Please do not go up on the roof or the stack yourself; call us and we will take a proper look.
- Visible tilt compared with the ridge or neighbouring stacks
- Cracks that run through bricks as well as joints
- Loose or missing pots and cracked flaunching
- Damp staining on the chimney breast or in the loft
Repair or rebuild
Small areas of failed mortar can sometimes be dealt with by repointing, which has its own page. A stack that leans, bulges or has cracks through the bricks themselves should be rebuilt, because pointing over movement only hides the fault and it will return.
If the damage is limited to the top few courses, we may only need to rebuild above the roofline. Where the lean starts lower, or the stack is cracked at the roof, the rebuild has to go down to sound brickwork before it is built back up.
How the rebuild is done
We set up a tower or scaffold, then dismantle the stack course by course, setting aside good bricks to reuse and matching any that have to be replaced. The stack is rebuilt in a suitable mortar, with lead flashings and a damp-proof tray where the design calls for it.
The pots are then bedded in a fresh flaunching that slopes water away from the flues. On a shared stack we agree access with the neighbour before the work begins, and we make good the roof and ceiling below once the stack is finished.
- Scaffold or tower set up with the street kept clear
- Stack taken down to sound brickwork
- Rebuilt to match the house, with new flaunching and pots re-bedded
- Roof around the stack checked and made good
What to ask your roofer
Ask how far down the stack will be taken, whether the lead work is included in the quote, and how the bricks will be matched. Ask who arranges the scaffold and how the neighbours will be told, because on a terrace the work nearly always affects someone else.
If the chimney is no longer needed, ask about reducing it instead. That needs an assessment first, with structural support to consider, and Building Regulations or planning checks may apply. We advise on all of this before any work starts.
Need a chimney looked at in Aberdare? See chimney repairs in Aberdare, or for the lead and mortar side of it, chimney flashing repairs and chimney repointing and repairs.
More Chimney Guides for Aberdare
Common Questions
Is a leaning chimney stack dangerous?
It can be. A stack that leans or has loose bricks may drop material onto the roof or the pavement, especially in high winds. Keep clear of the area beneath it, and call us so we can look at it and make it safe.
Can a cracked stack just be repointed?
Only if the cracks are in the mortar alone. Where bricks are split or the whole stack has moved, repointing only covers the problem. In that case we recommend a rebuild, and we will show you what we have found before you decide.
Will the rebuilt stack look like the old one?
We aim to match the original height, shape and brick as closely as we can, and reuse sound bricks where possible. On a terrace this keeps your stack in line with its neighbours, which matters on a visible hillside street.
Get a Chimney Looked At in Aberdare
Tell us what the roof is doing in Aberdare and we will look at it. Call 07766 547309, message us on WhatsApp or use the form below.