Chimney repair that stops the damp and keeps the stack standing

What our chimney repairs includes

• Repointing of the stack in mortar matched to the brick
• Replacement of cracked, spalled and frost-damaged bricks
• New flaunching around the pots, sloped to shed water
• Chimney pots re-bedded, replaced, or fitted with cowls and vented caps
• New lead flashings, trays, aprons, soakers and back gutters
• Full stack rebuild from the roofline in matching brick
• Chimney removal above the roof, with flue capped and the roof made good
• Scaffold, safe access and waste removal included in the quote

Chimney repair: stack, flaunching, flashings and pots

A chimney is the most exposed part of your house. It stands on its own in the wind, takes rain from every side and shrugs off frost until the mortar gives way. It also has four separate parts that fail separately: the brick stack, the flaunching and pots on top, the lead where it meets the roof, and the flue inside. Doyle Homes has over 25 years' experience of each, and a chimney repair done properly means treating the part that is failing, not covering all four with sealant.

Because a chimney sits through the roof, the state of the stack decides whether the rest of the roof stays dry. Water entering through a gap at the stack runs down the chimney breast and stains the bedroom wall. Our customers' reviews describe chimneys sorted as part of larger roof and lead jobs, and a chimney repointed alongside new grade 4 lead flashings.

How we diagnose a chimney before we quote

We start from safe access, with ladders, a tower or scaffold, and look at the stack face by face. We check the pointing for sandy, crumbling or recessed joints, tap the bricks for spalling, and check the stack for lean or bowing with a plumb line. The flaunching is checked for cracks, the pots for rocking, and the lead for gaps and lift.

Inside, we look at the chimney breast and the loft side of the stack for damp, white efflorescence salts and brown flue staining, because those tell us whether the water is coming from the weather or from condensation in the flue. A stack that bends to one side while its mortar crumbles suggests sulphate attack in the joints, which means a rebuild, not a repoint. You get photographs of what we find.

Chimney repointing

Repointing is the most common job on a stack, and the one done badly more than any other. We rake out failed mortar to a sound depth, brush out the dust, wet the joints and repoint in mortar matched to the brick. Soft old bricks need a softer, lime-rich mix that lets the wall breathe. Hard modern brick takes a stronger one. Using a hard cement mix on soft brick traps water and splits the faces.

We finish the joints to match the existing profile and colour, so the repair looks as if it was always there, and we protect the roof slopes, gutters and garden from falling debris with boards and sheeting while the work is under way. Where bricks are cracked, frost-damaged or spalled, we cut them out and replace them with matching units before pointing. See the weathered stack in our photographs from before the work, and the finished result after.

Flaunching, pots and cowls

The flaunching is the sloped mortar bed that holds the pots and sheds water off the top of the stack. When it cracks, water runs into the brickwork and the pots loosen. We chip off the failed flaunching, re-bed the pots on fresh mortar and form a new, sloped bed that throws water clear of the stack. Our photographs show new flaunching around a pot and a stack with fresh pots and scaffold alongside.

Cracked or missing pots are replaced to match. Where a flue is no longer used we fit a vented cap that keeps rain out and lets the flue breathe, which prevents damp rising in the chimney breast. Where a fire is in use, we fit a cowl suited to the flue.

Lead flashings and trays around the stack

Most leaks attributed to a chimney start at the lead. A back gutter behind the stack, soakers or step flashings up the sides and an apron across the front form a waterproof collar, and each can lift, split or open at the joints with age. We renew them in code 4 lead, chased into the brickwork and wedged, or fitted with lead clips and sealed, and we add a lead tray inside a rebuilt stack.

For the full detail on flashings, valleys and lead roofs, see our lead work page. In an emergency, such as a stack losing bricks in a gale, see emergency roof repairs: we make it safe the same day.

Rebuilding or removing a chimney stack

Chimney rebuild

When the brickwork is beyond a repair, we take the stack down to sound masonry, normally to the roofline, and rebuild it in matching brick with a lead tray, new pots and flaunching. Our photographs show an old stack being taken down and a rebuilt stack with new pots.

Chimney removal

If you no longer use the chimney, we take the stack down above the roof, cap and vent the flue, and make the roof good in matching tile or slate. If you want the chimney breast removed inside the house, the structure above needs supporting, and we run that through the surveyors, architects and builders we recommend, as part of our building work.

Chimney repair cost and your guarantee

Cost depends on the height and number of stacks, the work needed and the access, since a tall stack needs a scaffold or tower. Two stacks on one roof share the same access, so the second costs far less to repair than the first. Your written quote itemises materials and labour with no hidden costs, and we will beat any written quote. For a first idea of the numbers, read our roof repair cost guide.

All work is backed with a 20 year written guarantee, and we are fully insured. We carry out a risk assessment before every job.

Chimney repairs near you

We work from our Dunstable office across Bedfordshire, Hertfordshire, Buckinghamshire and North London. Local pages cover Luton, St Albans, Milton Keynes and Harpenden. Customers rate us 4.91 from 62 reviews on TrustATrader, 4.7 from 23 on Google and 9.63 from 73 on Checkatrade. Ring 01582 807949 for a free quote. If the whole roof is worn, see roof repairs and new roofs.

Signs you need us

• Crumbling, sandy or missing mortar between the bricks
• A stack leaning, bowing or showing cracks through the brickwork
• Cracked or loose mortar around the base of the pots
• White salt staining or brown flue stains spreading on the chimney breast
• Damp patches on the chimney breast in the bedroom or loft
• Lifted, split or gapped lead where the stack meets the roof
• Loose or missing chimney pots, or bricks falling onto the roof