Mutual and Gable Chimneys

Mutual chimneys will often carry flues from the neighbouring tenement as well as from your own and costs will be shared between both tenements. 

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Cross wall

Often made of brick inside the loft

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Chimney flashing to skew

More about flashings

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Sarking

More about roof timbers and your loft

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Mutual and gable chimneys are built at the top of cross or gable walls, the difference being that a mutual chimney is shared between two neighbouring buildings and the wall below is generally made of brick, even in older stone tenements. (Gable walls in older tenements are commonly built in a rubble or rough finished stone).

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A brick cross wall John GilbertExposed by demolition of the neighbouring building.

As the flues feed up through the walls, the stonework can be quite thin in some areas. The stone is vulnerable to decay, particularly high up where the flues gather and there is most exposure to the weather.  

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Stone gable wallJohn GilbertNote the decayed stonework where the flues run

Along with the skew, mutual chimneys form a firebreak between two tenements. Gaps in the wall inside the loft will allow smoke and fumes to escape into the loft and allow fire to spread to neighbouring properties. 

Mutual chimneys share many of the repair issues that affect all chimneys - problems with copings, stonework, render, flashings and pots.

See Chimneys for more information on defects.

Professional help recommended?

Although the work may appear straightforward, ensure your builder or tradespeople have the skills for the job. If in any doubt, get professional help to specify and organise the repair.

Further information

Historic Scotland Inform Guide 'Domestic Chimneys and Flues'