Tue 16 Dec 2014
Property News: All He Surveys
Chim chimenee, chim chimenee, chim chim cher-oo!
With Christmas fast approaching and winter setting in, it seems appropriate to focus on a building element that stands above the rest – often out of sight and out of mind – but this time of year a staple in European folklore for the legendary big bellied fella with a long beard and red clothes; jolly old Saint Nick (also known as Santa Claus).
A chimney (or middle English ‘chimenee’) is of course a structure, often constructed from bricks and mortar, containing a vertical flue leading from the throat of the fireplace to project from the roof, carried above the ridgeline of the building within a stack, designed to carry smoke to the outside atmosphere.
Cowls are traditionally fitted to chimney pots located on top of the chimney stack to increase the draught and prevent wind and rainwater entering into the building. Pots are held in position by a sloped mortar fillet known as flaunching; this also directs surface rainwater away. Flashings, often flexible lead material, are typically installed where the chimney passes through the roof coverings and are intended to eliminate rainwater from the roof void. The stack is named after the vertically stacked bricks (or sometimes stone) bound together by mortar.
Chimneys have been an important part of buildings for centuries. However, before the 12th century, the main fire set was said to be positioned within the centre of the property. Notoriously inefficient and dangerous, smoke would escape through a purpose made gap in the roof covering, although most enclosed dwellings stayed full of smoke. Cheaper ineffective chimneys were later created from timber, waddle and daub, however these remained susceptible to spread of fire.
The evolution of chimneys has evolved significantly in modern years. Nowadays, buildings are designed without the necessity for chimneys due to sustainable heating systems. Refurbished buildings are seeing chimney stacks being demolished or capped off with the chimney breasts removed for extra floor space (always seek local authority approval). Alternatively, some refurbishment properties are utilising the existing flues, which are retrospectively lined and a contemporary wood burning stove installed.
Chimneys are stacked up in many different shapes and sizes and all serve the same function if maintained correctly.
Potential maintenance problems could include:
1. Structural instability
2. Sulphate attack
3. Friable mortar
4. Spalling brickwork
5. Rainwater penetration
The above list is not exhaustive, so don’t ignore any other problems; consult a local Chartered Surveyor to inspect any defects and report upon the best method of repair. And, remember, if you have an open fire do ensure it is regularly cleaned, particularly in time for Christmas Eve. www.grantjamescrossley.com Follow me: @MrGrantCrossley