Chimney Repair near you

A stack is a thin piece of masonry standing in the weather with nothing over it. Rain soaks into the brick, frost expands what the brick absorbed, and the mortar, which on an older house is softer than the brick by design, gives up first. Once the joints are open the stack takes on more water, and a wet stack in a hard frost loses brick faces rather than just pointing.

The inside does its own damage. Flue gases are warm and acidic, and where they condense in an unlined or poorly lined flue the salts they carry migrate through the masonry and show up as staining on the chimney breast indoors. Sealing a redundant flue at both ends makes this worse rather than better, because a flue with no air movement stays damp; the usual approach is to cap the pot in a way that still ventilates and to vent the breast at the bottom.

Most so-called roof leaks near a chimney are stack leaks. Water tracks down the outside of the brickwork, past failed flashings or through a missing damp-proof tray, and arrives on a ceiling several feet from where it got in. Approved Document C is the England guidance on resistance to moisture in floors, walls and roofs, with examples of damp proofing and ventilation provisions, and a stack that has been quietly wetting a wall for years is a damp problem long before it is a roofing one.

Repointing a stack or renewing a flashing is repair work. Installing or replacing an appliance, a flue or a liner is not, and GOV.UK sets out two lawful routes for work needing approval: apply to a building control body, meaning your local authority's building control department or a private registered building control approver, or use someone registered with a competent person scheme, in which case you do not have to get approval yourself. The warning attached to skipping it is that without approval you will not have the certificates of compliance you may need when you want to sell your home.

Planning permission is a separate question and usually turns on a new flue rather than a repair. The Planning Portal's position for houses is that flues on the rear or side elevation of the building are allowed to a maximum of one metre above the highest part of the roof, and that in a designated area the flue should not be fitted on the principal or side elevation that fronts a highway. Those allowances apply to houses, not to flats or maisonettes, and the guidance advises checking with the local planning authority first where the building is listed or in a designated area.

Listed buildings are stricter than most homeowners expect. National planning practice guidance states that works to alter a listed building in a way that affects its character as a building of special architectural or historic interest require listed building consent, that undertaking such works without consent is a criminal offence, and that even minor works have the potential to cause substantial harm depending on the nature of their impact on the asset and its setting. Rebuilding a stack in the wrong brick, or changing the pots, is exactly the sort of change a conservation officer will want to see first.

Diagnosis starts from the ground with binoculars and in the loft with a torch, looking for where water is arriving rather than where the stain has spread to. Only then is it worth getting up: access is a legal decision, and HSE's guidance is that ladders may be used for work at height where an assessment of the risk has shown that equipment offering a higher level of fall protection is not justified, that alternative equipment is recommended where the task would mean more than 30 minutes at a time on a leaning ladder or stepladder, that ladders should only be used where they will be level and stable and can be secured where it is reasonably practicable to do so, and that the user must be competent or supervised by someone who is. Repointing a whole stack is not a thirty-minute job, which is why a serious quotation has a scaffold on it.

The repair itself works from the top down. Pots are lifted and re-bedded, the flaunching is cut out and renewed to a fall so water runs off rather than sits, open joints are raked out to a proper depth and repointed in a mortar that matches the existing in strength and appearance, and any brick that has lost its face is cut out and replaced with a matching unit turned to present a sound face. Where the stack has moved or the brickwork above the roof line is beyond pointing, the usual answer is to take it down to a sound course and rebuild, saving and re-using the original bricks where they are good enough.

Flashings and the flue finish the job. Lead is renewed in lengths short enough to allow the metal to move, stepped into the raked joints and dressed over the covering, with a soaker and back gutter arrangement appropriate to the roof. If an appliance is being connected, the flue is the competent person's territory rather than the mason's. Scotland's technical handbook makes the maintenance point explicitly on the removal of products of combustion, requiring that access should be provided for inspection and cleaning of the flue and the appliance, with access hatches of at least 300mm by 300mm positioned within 1.5 metres of flue joints, and it names inadequate maintenance of chimneys, including routine cleaning of flues, among the causes of chimney fires.

Repointing is the right answer where the bricks are sound and only the joints have gone. Rebuilding above the roof line is the answer where the stack leans, where brick faces have spalled across the weather elevation, or where repointing would simply be filling between bricks that no longer have a face to hold it. Removing a redundant stack is a third option and a tempting one, but it is structural work: Approved Document A covers the loadings on a building and the construction of the structural elements including the foundations, walls, floors, roofs and chimneys, and a breast and stack that has been part of a wall for a century is holding something up.

Removal also brings in the neighbours on a terrace or a semi. GOV.UK's guidance on the Party Wall etc. Act 1996, which applies in England and Wales, covers work to an existing party wall or party structure and names removing chimney breasts among the examples, and requires a building owner proposing such work to give adjoining owners notice in the way the Act sets down. Section 3 of the Act requires a party structure notice, stating the name and address of the building owner, the nature and particulars of the proposed work and the date on which the work will begin, to be served at least two months before that date. Budget the time as well as the money.