Allchimneys offer a comprehensive chimney repair and maintenance service, our team of professionals have worked on every type of chimney imaginable.
Here are some of the chimney repair & maintenance services that Allchimneys provide:
- Chimney pointing/repointing of chimney brickwork.
- Replacement & repair of damaged chimney pots
- Chimney capping and cowl installers.
- Chimney surveys – Chimney inspection and Testing
- Increasing chimney draw.
- Identifying causes of down draught & implementing solutions.
- Rebuilding domestic brick chimney stacks.
- Smoke testing & chimney leak detection.
- Chimney Aspirator & anti-down-draught chimney cowl fitting.
- Chimney capping & vent repairs.
- CCTV chimney surveys.
- Chimney brickwork cleaning & restoration.
- Lightning protection/ Lightning conductor fitting.
- Chimney breast repair, removal & fabrication/installation of structural
Read more detail about our Chimney Repair services below, or Contact us now with any enquiries.
Chimney pot repairs
Allchimneys carry out chimney repairs including:
- Chimney pot installation
- Chimney pot repair and replacement
Chimney pots are the flue terminal to a domestic brick built flue. Typically, a chimney pot is 200mm/8” in internal diameter and stands up from the chimney brickwork 300mm/12”. Most local semi-detached property’s in the London and Essex area would have a shared brick chimney stack on the party wall containing 8 chimney flues, 4 flues to each property, each flue having its own terminal, the chimney pot.
Chimney pot defects which would require attention would be a chimney pot that is leaning or out of line as described in the paragraph above or in worse case has vertical or cracks visible around the circumference, normally at the chimney pot base above the flaunching. Causes of chimney pot cracking are movement in the chimney structure applying pressure to the pot or previous chimney fires that have raised the temperature of the chimney pot to as much as 1100 degrees Celsius. A chimney fire that could have taken place well before the current owner.
Chimney brickwork/pointing repairs
Allchimneys carry out chimney repairs including
- Chimney testing and inspection
- Chimney pointing
- Chimney rebuilds
A common chimney repair which we undertake would be repointing. Open joints in brickwork should be raked out to a sound depth and repointed. Sand/Cement mortar is applied to the gaps between the chimney brickwork by pointing trowel to the desired finish such as weather struck.
Chimneys in bad state of repair may have cracks appearing vertically and have the appearance from the ground that the head of the chimney is spawling or the chimney is leaning. Signs of early chimney decay would be chimney pots being at an angle or ‘out of line’. Chimney pots at odd angles would indicate the chimney flaunching (the sand/cement finish which retains the chimney pots or terminals to the chimney top) is cracked and allowing ingress of water to internal chimney brickwork and flue. Attention should always be given to prevent water penetration to chimney flues. Water ingress can freeze in colder winter conditions and cause havoc to the structural integrity of a brick chimney or flue system. Damp issues becoming an issue of chimney breasts in bedrooms below.
Chimney pot repairs
Allchimneys carry out chimney repairs including:
- Chimney pot installation
- Chimney pot repair and replacement
Chimney pots are the flue terminal to a domestic brick built flue. Typically, a chimney pot is 200mm/8” in internal diameter and stands up from the chimney brickwork 300mm/12”. Most local semi-detached property’s in the London and Essex area would have a shared brick chimney stack on the party wall containing 8 chimney flues, 4 flues to each property, each flue having its own terminal, the chimney pot.
Chimney pot defects which would require attention would be a chimney pot that is leaning or out of line as described in the paragraph above or in worse case has vertical or cracks visible around the circumference, normally at the chimney pot base above the flaunching. Causes of chimney pot cracking are movement in the chimney structure applying pressure to the pot or previous chimney fires that have raised the temperature of the chimney pot to as much as 1100 degrees Celsius. A chimney fire that could have taken place well before the current owner.
Leaking flues/ the smell of smoke in the property (chimney repair)
- Chimney smoke testing
- Chimney leak detection
- Chimney inspection
- Chimney lining
A domestic brick chimney is typically 9”/225mm square. One chimney flue servicing one fireplace opening. Above the fireplace opening or ‘Builders opening’ the internal brickwork steps from fireplace width at lintel to reduce its size to the base of the 9” square flue. This area of the fireplace is known as the ‘brick gather’. The flue rises from this point to termination at the head of the chimney. Often passing through bedrooms/fireplace openings above being joined in parallel to other flues in the ‘Chimney breast’. The division of the flues within the chimney breast is the width of one brick or 100mm. This division brickwork is called the ‘midfeather’.
Chimney/flue leaks - Clay/ceramic chimney lining (chimney lining repair)
From the 1960’s building control/building regulation stated that all new brick construction chimneys were to be installed with a chimney lining. This chimney lining was typically of ceramic or clay chimney liner sections. Very similar build to a chimney pot with male/female ends. These clay chimney liner sections with interlocked with suitable joint sealant and installed the entire length of the chimney flue from fireplace brick gather to chimney pot termination. These chimney linings contained within the 9” flue construction brickwork of the chimney. Flue gas leaks reported from clay chimney linings are mostly due to one main cause.
Leaking flue/ chimney leakage – Rendered chimney lining (chimney leak repair)
Before the 1960’s change in chimney building regulation all brick chimneys were internally rendered. The bricklayer would build his chimney or chimney breast and render the internal face of the flue with a weak mix sand/cement/lime mortar. This mix was the chimney lining.
Over time there are many factors which can lead to the deterioration of this form of chimney lining.
- Water ingress from above such as open chimney pots without suitable chimney cowls or possible defects left unrepaired to the chimney head
- The sulphur content in soot from burning coal and other solid fuels. This sulphur content especially when in contact with rainwater or condensing flue gases is very acidic.
- Breach in chimney brickwork – The ‘midfeather’ brickwork may have become dislodged. External chimney brickwork may have been removed and altered during home renovation. Basically, there is a hole in the chimney allowing for the flue gases or chimney smoke to leave the flue and enter the property.
Chimney flashing/ lead flashing/ cement fillet (chimney flashing repair)
Allchimneys carry out chimney repairs including:
- Lead flashing repair or replacement
Rainwater leakage from a chimney into the roof or loft space can also be a common chimney repair. Lead step flashing:
Lead chimney flashings are generally called ‘Step flashing’ as they step with the roof pitch. These lead flashings are plugged along the brickwork bed joint and then finished with a sand/cement pointing to weather the join. In time the lead plugs can become loose or the pointing cracks, both causing the lead step flashing to dislodge from the chimney and allow water to penetrate the roof area. In some cases the leadwork can be redressed and fastened back in place or new step flashings can be made.
Sand/Cement fillet chimney flashing:
A low cost chimney flashing is a sand/cement fillet between chimney brick and roof covering. This isn’t the best solution and often requires repair. The fillet cracks due to movement in the structure and allows water to penetrate through the gap between the chimney and the roof tile covering. This type of chimney flashing is best replaced with a lead step flashing.
Chimney cowls or chimney cappings (chimney repairs and maintenance)
Allchimneys carry out chimney repairs including:
- Rain cap fitting
- Chimney cowl installation
- Chimney capping
Chimney caps/capping (installing a chimney capping)
A chimney caping is utilised to cap the chimney pot of a disused flue. This flue once capped should not be used as it effectively plugs the top the flue and prevents any combustion gases from leaving the chimney system. A more traditional capping would be of clay construction and insert into and existing chimney pot. These types of capping are commonly called ‘Elephants feet’, ‘Pepper pots’ or ‘Ridge tile cappings’. Benefits of installing a chimney capping are:
- The installation of a chimney cap can greatly reduce heat loss from the room in which the fireplace is installed.
- A chimney cap will prevent any unwanted birds from falling into the flue and potentially entering the house or being trapped behind a closed fireplace.
- Rainwater penetration to the chimney flue can also be prevented by a chimney capping which in turn to minimise chimney lining decay.
Chimney cowl/chimney rain cap/chimney terminal (chimney cowl installation)
A chimney cowl is generally used to prevent rainwater from entering a flue or chimney system which is in use. Other types of cowl or rain caps have the addition of a bird guard mesh preventing birds from falling into your chimney flue. A rain cap with bird guard mesh is a great addition to any non-condensing chimney system and should be considering during annual chimney maintenance or routine chimney servicing or inspection.
Anti – downdraft cowls / Anti – downdraught cowls / down draft problems (chimney repair)
Allchimneys are installers of anti-downdraft cowls.
‘Chimney down draft’ is a term used to describe when a chimney has no draw and flue gases are travelling in a downward direction and into the property. The reverse of a correctly working chimney. This can be very dangerous.
- Down draft is caused by differences in air pressure or pressure zones.
- Can be caused by the addition of air extraction fans in a property such as a kitchen extract fan.
- Loft extensions or adjacent higher buildings can change air movement and pressure zones around the chimney pot or terminal.
- Chimneys which have been reduced in height commonly are effected by down draft.
An onsite chimney inspection would be required to determine the exact cause of downdraft to a property. A solution can be an anti-downdraft cowl.
Down draft/down draught cowls come in many designs. The most common which is generally considered the best as it also increases chimney draw is a ‘spinning cowl’. As this louvred ball like cowl spins in the wind it draws air up through the chimney flue maximising chimney draft.
Chimney draw and smoke testing
Allchimneys carry out chimney testing and inspection including:
- Chimney surveys
- Flue testing and inspection
- Smoke testing of chimney flues (draw test and soundness testing of chimneys using smoke pellets)
A chimney s draw or draw test can be made by use of a smoke pellet or ‘smoke bomb’. There are two main smoke tests as described in the building regulations. ‘Smoke test 1’ And ‘Smoke test 2’.
Chimney flue smoke test 1:
Commonly described as a ‘smoke draw test’, a ‘smoke evacuation test’ or a ‘spillage test’. This chimney smoke test indicates if there is any spillage into the room or smoke escaping from the fireplace opening or appliance. Effectively testing if the chimney is drawing correctly and is safe to use.
The doors and windows should be closed.
The heating appliance or chimney flue is first warmed. This generally is by use of a heat gun.
A smoke pellet is then lit and placed in the flue or connected appliance. The smoke generated by the pellet is observed. The smoke should remain within the fireplace opening or appliance with no spillage into the room.
Chimney flue smoke test 2:
Commonly described as a smoke soundness test or pressure test. This flue smoke test is carried out to determine whether a flue is leaking and if there are any structural defects. The flue is effectively filled with smoke, capped at top and bottom and then visual inspected where access is available. This smoke soundness test can be carried out of a domestic brick chimney for an open fire, a metal boiler flue system or a Twin Wall Insulated chimney for a wood burning stove.
The chimney is first swept. A smoke pellet is lite and placed in the fire box or solid fuel heating appliance. The smoke is allowed to draw through the entire chimney until termination. When the smoke reaches the chimney pot or terminal this point is blocked, normally with a plastic sack. At the same time the firebox opening is covered. The chimney flue then fills with smoke.
For a period of no more than 15 minutes a visual inspection is carried out. The full length of the brick flue (through bedrooms and loft space) is examined for any leaking smoke. With a a factory made Twin Wall Insulated flue, every joint would be examined for evidence of leakage.
Once inspection is carried out the temporary coverings are removed and smoke is released at flue termination.