A chimney breast is a portion of a

chimney A chimney is an architectural ventilation structure made of masonry, clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler, stove, furnace, incinerator, or fireplace from human living areas. Chimneys are typical ...

which projects forward from a wall to accommodate a

fireplace A fireplace or hearth is a structure made of brick, stone or metal designed to contain a fire. Fireplaces are used for the relaxing ambiance they create and for heating a room. Modern fireplaces vary in heat efficiency, depending on the design. ...

. Typically on the ground floor of a structure, the

masonry Masonry is the craft of building a structure with brick, stone, or similar material, including mortar plastering which are often laid in, bound, and pasted together by mortar (masonry), mortar. The term ''masonry'' can also refer to the buildin ...

extends upwards, containing a

flue A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. Historically the term flue meant the chimney itself. In the United States, they a ...

which carries

smoke Smoke is an aerosol (a suspension of airborne particulates and gases) emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwante ...

out of the building through a chimney stack. Chimney

jamb In architecture Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and cons ...

s similarly project from the wall, but they do so on either side of the fireplace and serve to support the chimney breast. The interior of a chimney breast is commonly filled with

brickwork Brickwork is masonry produced by a bricklayer, using bricks and mortar. Typically, rows of bricks called '' courses'' are laid on top of one another to build up a structure such as a brick wall. Bricks may be differentiated from blocks by ...

concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

. The construction and appearance of a chimney breast can vary according to function and style. English and American builders more often treat the chimney breast and fireplace as distinct architectural features, whereas French buildings have gradually trended towards concealed construction.

False chimney breasts

False chimney breasts are sometimes constructed around a twin-walled flue or against a wall pierced by a flue for purely cosmetic purposes. Typically they will consist of a timber frame or stud work covered with plaster board and a plaster skim. If the false breast contains a flue, it may be necessary to line it with a

refractory In materials science, a refractory (or refractory material) is a material that is resistant to decomposition by heat or chemical attack and that retains its strength and rigidity at high temperatures. They are inorganic, non-metallic compound ...

material such as

vermiculite Vermiculite is a hydrous phyllosilicate mineral which undergoes significant expansion when heated. Exfoliation occurs when the mineral is heated sufficiently; commercial furnaces can routinely produce this effect. Vermiculite forms by the weathe ...

. Usually, additional cosmetic features will be added, such as cosmetic beams,

overmantel The fireplace mantel or mantelpiece, also known as a chimneypiece, originated in medieval times as a hood that projected over a fire grate to catch the smoke. The term has evolved to include the decorative framework around the fireplace, and ...

s or fireplace surrounds.

Removal

Chimney breasts often become redundant with respect to their function as a chimney after the installation of alternative heating methods, such as

central heating A central heating system provides warmth to a number of spaces within a building from one main source of heat. A central heating system has a Furnace (central heating), furnace that converts fuel or electricity to heat through processes. The he ...

. Removing a chimney breast can create more floor space and a more regular-shaped room, but since chimney breasts often have a structural function, removal requires careful planning. It’s essential to consult a structural engineer and follow building regulations. Use appropriate PPE, especially dust masks (FFP3) to avoid inhaling fine particles, such as silica and asbestos, which can be smaller than 2.5 microns. These particles can be harmful if inhaled, so professional advice and asbestos testing are recommended. The removal of part (especially the lower part) of a breast can cause uneven loading on a wall, especially if the upper part is not suitably supported, ideally on an

I-beam An I-beam is any of various structural members with an - (serif capital letter 'I') or H-shaped cross section (geometry), cross-section. Technical terms for similar items include H-beam, I-profile, universal column (UC), w-beam (for "wide flang ...

. In some cases, support on a steel beam and post, or by gallows brackets may be acceptable with party wall agreement. A gallows bracket cannot be used on both sides of the party wall without removing the chimney stack. Other factors that need to be considered when removing a chimney breast are: fire safety particular for party walls, noise insulation, effect on neighbour's chimney, damp prevention, and ventilation.

References

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External links

How to wallpaper a chimney breast
Chimneys