Why Important
Chimneys are an important part of the Birkenhead skyline throughout the Birkenhead Heritage Area. Each room in a traditional property would have had an open fire, as this was the only means of heating them.
What to look for
Flues were generally built into the thick masonry party walls and gathered at roof level into big stone stacks with rows of buff clay chimneypots.
Stone finishes to Georgian chimneys vary with prominent chimneys built of ashlar (smooth stone) and less prominent ones with a droved or broached finish to the stones.
Rear chimneys are often rubble with dressed broached and droved quoins. Flues are not generally used for open fires now but many take flue-liners for gas boilers and gas-effect fires.
When to look
Chimneys should be inspected to ensure that they are pointed and that the haunching round the pots is sound.
How to fix
Chimney-pots need cowls for these, which should be in buff-coloured clay to match the pot rather than metal.
Where flues are no longer in use, they can be capped with clay ventilators, which stop rain running down the inner face but allow a small amount of air movement within the flue. Haunching of cement mortar around the pots can crack. Removing this mortar may be impossible without breaking the clay pots and it is better to manage the situation by filling any cracks with traditional lime mortar than breaking the cement mortar out. New and replacement pots should match the existing ones.
Avoiding creating problems
Often the haunching has been reapplied in a strong cement mortar, which is more likely to crack than a traditional lime mortar.
Historical background
Before the Georgian period chimneys were often built of rubble stone intended to be lime-harled, with thick decoratively moulded stone caps.