Chimney breast removal

Why people remove a chimney breast

A chimney breast juts into the room and dictates where furniture can go. Removing it on the ground floor can square off a living room or make space for a kitchen run, and removing it upstairs can free up a wardrobe wall in a bedroom. In older terraces and semis the breast often serves a fireplace that has not been used in decades, so the space is genuinely wasted.

What you cannot do is simply knock the breast out and hope. The chimney above, and the stack on the roof, still need support, and that is what makes this a structural job rather than demolition.

How the remaining chimney is supported

If the breast is removed at ground floor but the chimney continues above, the upper section must be supported. The usual methods are a steel beam (an RSJ) across the opening, designed by a structural engineer, or gallows brackets fixed to the party wall where the engineer and Building Control accept them. The support has to carry the weight of the brickwork above and transfer it safely to the walls that remain.

Removing the whole chimney, breast and stack together, is the other option. It avoids the need for internal support but means roof and brickwork repairs where the stack came out, and on a shared chimney it means agreeing the work with the neighbour.

Party wall and Building Regulations

Chimney breasts are very often built into a party wall shared with the neighbour, so the Party Wall Act usually applies and a notice has to be served before work starts. Building Regulations approval is needed too, because the work affects the structure of the house. The engineer's calculations and the Building Control inspector's visits are part of the job, not optional extras.

If the chimney is shared, the neighbour's side has to stay weathertight and supported as well, and their flues must not be affected. This is routine work but it has to be done in the right order.

Making good afterwards

Once the breast is out and the support is in, the floor, walls and ceiling are made good: the gap in the floorboards is filled, the wall is plastered where the breast stood, and the skirting and decoration are tidied up. Where the breast is removed upstairs but kept below, or vice versa, ventilation of the remaining flue is needed to stop damp building up inside the old chimney.

One floor, two floors or the whole chimney

You do not have to remove the whole breast. Taking out the ground-floor breast only, and keeping the bedroom chimney breast above, is common where the upstairs alcoves are useful. Taking out both floors but leaving the stack on the roof is another option, though the stack then needs supporting at roof level. Removing everything, breast and stack, gives the cleanest result inside but adds roof repairs and, on a shared stack, agreement with the neighbour.

Each option has a different structural design and a different amount of making good, so it is worth deciding how much space you actually need before the engineer draws anything up. We talk through the options at the site visit.

What affects the cost

Cost depends on whether the breast is removed at one floor or two, whether the stack is coming down too, the support method the engineer specifies, party wall and Building Control requirements, and how much making good is needed. We look at the chimney, talk through the options and give a free written estimate.