Chimney Breast

A chimney breast is a portion of a wall which projects forward to accommodate a chimney flue within its structure. Typically found in older buildings, chimney breasts are a crucial part of the chimney system, housing the flue that channels smoke and gases from the fireplace to the outside. The design and condition of the chimney breast can significantly impact the efficiency and safety of the fireplace.

Importantly from a damp perspective, chimney breasts are typically made of a single skin of bricks, whereas most walls are made of two skins. If not used as for heating, this difference in thickness of wall could localised heat loss, increasing the risk of condensation, either below the chimney , in the sub-floor void, or on an exterior wall.

Chimneys were often used for burning coal. Burn coal can release hygroscopic salts onto the surface of the chimney breast or nearby wall. Hygroscopic salts look damp, and are often mistaken for damaged roofs or even rising damp.

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