Removing a chimney breast normally needs building regulations approval and a structural design for the chimney that remains. Where it affects a party wall or shared construction, the neighbour's structure and flues must also be considered; their chimney cannot be assumed to match yours. [1] [2]
Decide exactly what is being removed
A chimney breast is the projection inside the building; the stack is the part above the roof. Removing a ground-floor breast while retaining masonry on the floor above creates a different structural problem from removing the chimney throughout the house. Make the extent of removal clear on the drawings. [1]
The engineer needs to consider the weight and stability of the retained masonry, the condition of the wall and how loads will reach suitable supports. Richmond's building control guidance also identifies the floor left behind after a hearth is removed: the surrounding joists and the new floor arrangement need assessment, not simply a patch in the boards. [3]
Gallows brackets are not a universal solution
A gallows bracket is a support fixed into a wall, but its suitability depends on the actual construction. A steel beam or another engineered arrangement may be needed instead. Redbridge's guidance sets conditions for bracket use and highlights the significance of the neighbouring chimney breast already having been removed. Treat that as a reason for a project-specific design, not a standard detail suitable across London. [2]
Do not buy brackets or order steel before the engineer has checked the retained chimney and supporting masonry. Richmond's guidance similarly identifies limitations involving masonry and adjoining chimney arrangements. The important question is whether the complete support system is suitable for this building, rather than whether a particular product is commonly sold. [3]
Protect the neighbour's side
Removing a breast from a party wall is among the works covered in the government's Party Wall Act booklet. Work to an existing party structure normally requires at least two months' notice, unless the relevant parties agree an earlier start through the applicable procedure. Consent to the notice does not replace structural design or building regulations approval. [4]
The design also needs to preserve the separation between the homes. Redbridge identifies the risk of damage to neighbouring flues and the need to maintain appropriate fire separation. Establish the flue arrangement before removal and agree how any affected adjoining flue will be checked. [2]
Deal with services, ventilation and making good
Any gas work must be carried out by a suitably qualified Gas Safe registered engineer. Do not leave an appliance connected to a flue that the works have made unsafe, or block ventilation that an appliance requires. [5]
Unused retained flues and the remaining chimney need suitable treatment to avoid ventilation and damp problems. The details should be included in the work, along with structural support, floor repairs and the necessary fire and sound separation—not left as decoration-only items. [3]
Internal location is not an exemption from listed building consent: check before removing features that contribute to a listed building's special character. [6]
Check later fire-protection specifications
The published Approved Document B change removing national fire-resistance classifications takes effect on 2 September 2029, with transitional arrangements. Recheck the specified evidence for any new fire-protected support if the works fall under that later guidance. [7]