If you are facing a chimney rebuild in Sutton and want to know exactly what the job involves from the first visit to the final clean-up, this page sets it out step by step.
Call any time. Calls are answered day and night and passed straight to our roofers.
A chimney rebuild is not a small job. It involves scaffold or a working platform, structural brickwork above the roofline, lead work and several days on site depending on the stack. Homeowners who understand the sequence of work can ask better questions, spot if something is being skipped and feel less anxious about what is happening on their roof. Here is how a proper chimney rebuild is carried out, from the first look to the day we pack up and leave.
The job starts with a proper inspection of the chimney, not a glance from the pavement. A roofer who quotes without getting up close to the stack is guessing. From the ground you can see a lean or a missing pot, but you cannot assess the depth of mortar erosion, the condition of individual bricks, whether the flashing is correctly dressed into the joints or whether there is a DPC present. Any of those details can change the scope of work significantly.
We use a roof ladder or erect scaffold to get eyes on the stack at close range. On that visit we assess: how many courses need to come down, the condition of the bricks in the remaining courses, the state of the existing flashings, the condition of the flaunching, and whether there are any issues at the base of the stack where it meets the roof covering. We will also ask whether the chimney is in use or redundant, because that affects how the flue is treated at the top.
After the inspection we can give you a realistic scope of work and a price based on what we have actually seen. If brick matching is needed, we will discuss what the options are at this stage.
Before any brickwork is touched, safe working access has to be in place. For most domestic chimney rebuilds, that means scaffold erected around the chimney stack. On a single-storey extension or a low outrigger, a roof ladder and a properly footed ladder may be sufficient, but for a full rebuild on a main roof above the first floor, scaffold is the appropriate method.
Scaffold is hired from a scaffolding contractor. The erection and dismantling is a separate cost from the rebuild itself, and it is worth understanding that when comparing quotes. A quote that appears cheaper may simply have left scaffold out. For an average domestic chimney rebuild, scaffold hire typically adds £400 to £800 to the overall cost, depending on the height and configuration required. Some properties need additional boards or ties due to the roof pitch or the position of the stack.
Once scaffold is up, we can work safely and correctly without rushing. Good brickwork cannot be done at arm's length from a ladder.
The existing chimney above the roofline is carefully taken down course by course to the last sound course of brickwork. We do not take down more than necessary. Each brick is assessed as we go, and where a brick in the lower section is sound and well-bonded, we stop there. The debris is bagged and lowered down rather than thrown from the roof, and a dust sheet or debris net is used to protect the roof covering below.
Taking down a chimney stack produces a significant amount of rubble for the size of the job. Broken bricks, old lime mortar and dried flaunching all need to be cleared from the roof carefully. This is part of the work, not a detail to be rushed.
At this stage the top of the remaining courses is cleaned back and checked for soundness before rebuilding begins. If the original stack had a DPC and it is in reasonable condition, we inspect it. More often on older stacks there is no DPC present at all, and a new one goes in at this stage.
A damp proof course at the level where the stack meets the roof is a building standard requirement and a practical necessity. It is a physical membrane, laid on the top of the last sound course before the rebuild begins, that prevents moisture from rising from the roof junction into the brickwork above it.
This is fitted before a single new brick is laid. It takes perhaps twenty minutes but it is a step that should not be omitted. If a roofer goes straight from clearing the old courses to laying new bricks without mentioning a DPC, ask the question directly.
The new brickwork goes up in courses, with each course checked for level and plumb as the work progresses. Mortar is mixed to the correct specification for the property - a lime-based mix for older buildings, a stronger mix for modern brickwork. Joints are struck to match the profile of the existing brickwork below, so the rebuild blends visually with the courses that remain.
Bricks are bonded in the correct pattern (typically English or Flemish bond on older stacks, stretcher bond on more modern ones) to ensure the joints do not line up vertically and the stack has structural integrity. Corner bricks are particularly important - cutting corners (literally) on quoin bricks weakens the stack.
The rebuild is carried out over one or more days depending on how many courses are required. Freshly laid mortar needs time to cure before the next stage, particularly in cooler weather. In winter, mortar joints may need to be protected from frost for the first 24 to 48 hours while they set.
New lead flashings are fitted once the brickwork has been given time to begin curing. The sequence is: soakers (individual pieces of lead laid between each course of tiles or slates at the sides of the chimney), then step flashings (which overlap the soakers and are fixed into the mortar joints), then the front apron flashing and the back gutter.
Each piece of lead is cut, shaped and dressed to fit the specific dimensions of the chimney and the roof. There is no such thing as an off-the-shelf chimney flashing kit that fits every stack correctly. The joints into which the flashings are dressed are raked out, the lead is tucked in and fixed with lead wedges, then pointed over with mortar. This method holds the flashing securely and lasts far longer than surface-applied sealant.
The back gutter, at the upslope side of the chimney, is the most critical piece. It collects water running down the roof above the chimney and diverts it to either side. If it is not formed correctly, or if the lead is not wide enough, water backs up behind the chimney and leaks under the roof covering.
The chimney pot is re-set on a fresh bed of flaunching - a mortar fillet shaped to slope away from the pot and shed water. Old, cracked flaunching is completely removed before the new bed is laid. If the existing pot is cracked or damaged, a replacement is fitted at this stage.
For redundant chimneys, a half-round clay cap or a ventilated cowl is fitted over the pot to keep rain and wildlife out while still allowing the flue to breathe. Sealing a flue completely with mortar or a solid cap can cause condensation to build up inside the chimney breast.
Once the flashings and pot are in place, the scaffold boards are cleared of debris, any mortar that has dropped onto the roof covering is removed, and the gutters directly below the work are checked and cleared if needed. The scaffold is then struck (dismantled) by the scaffolding contractor, usually a day or two after the roofing work is complete.
We do a final check of the finished stack from scaffold before it comes down: mortar joints, flashing dresssing, flaunching profile and the plumb of the completed stack. Once scaffold is gone, close-up access to the stack is not straightforward, so anything that needs correcting is dealt with before it is struck.
We carry out chimney rebuilds in Sutton and the surrounding area. A full chimney rebuild on a standard domestic property typically costs between £1,500 and £3,500 for the brickwork and flashings, with scaffold costs on top of that. Call us to arrange an inspection and we will give you a clear account of what your chimney needs.
No obligation · We'll call you to arrange a free visit
Call any time. Calls are answered day and night and passed straight to our roofers.
