Flaunching is the term for the mortar bedding installed at the top of a chimney stack. Formed using a strong cement-based mortar, the role of chimney flaunching is two-fold. Firstly, it provides a stable base into which chimney pots are bedded, ensuring a secure fixing able to withstand the wind and rain to which chimneys are exposed. The second function of chimney flaunching is to discharge water from the top of the stack quickly to prevent moisture being absorbed by the porous masonry beneath.
Because of its constant exposure to the elements and the relative brittle nature of cement-based mortars, chimney flaunching is prone to cracking which can allow water to leak into the building below. If not addressed, cracks in flaunching can develop and cause chimney pots to loosen giving rise to the possibility of pots falling from the chimney stack. This presents a risk to safety and potential damage to the roof covering.
The key to avoiding the damage associated with failed chimney flaunching is acting quickly however, flaunching is generally not easily accessible for inspection. Periodic drone surveys are a great way to monitor the condition of chimney stacks without the expense of scaffolding. If you’re buying a property, be sure to have a roof inspection carried out by an experienced roofing contractor.
Cracks can be repaired relatively inexpensively using epoxy resin products but once the cracks develop, replacement of flaunching is often required. In either scenario, the safety of those carrying out the work should never be compromised which invariably requires scaffolding.
Daniel James Construction Services are experts in chimney repair. Contact our experienced team for reliable advice on chimney stack maintenance and repairs.