A chimney stack is the most exposed masonry on your house, and on the Llandudno coast it weathers fast. This page covers chimney repointing, flaunching, cowls and capping — what each involves, what it costs, and why the right mortar makes the difference between a 10-year and a 30-year repair.
What Chimney Repointing Involves
Repointing renews the mortar joints in the stack's brickwork. We rake the eroded joints back to sound material — usually 15–20mm — brush them out, and repoint in mortar matched to the original. On Llandudno's period properties that means NHL (natural hydraulic lime) mortar, not modern cement, for reasons that matter (see below). Alongside repointing we deal with the flaunching — the mortar fillet that beds the pots — and fit cowls or capping where the flue needs protecting or closing off.
Why the Mortar Matters
The single most common mistake we correct on Llandudno chimneys is cement pointing applied to soft period brick. Cement is harder than the brick around it, so instead of the joint weathering, the brick face itself spalls and crumbles — accelerating decay rather than arresting it. NHL lime mortar is softer and breathable: it flexes with thermal movement, lets the masonry dry out, and sacrifices itself before the brick. On a stack you want to last, the mortar specification is not a detail — it is the whole job.
Key fact: Repointing of historic and soft-brick masonry should use lime-based mortar rather than hard cement, which traps moisture and causes the brick face to spall — a leading cause of accelerated masonry decay. Source: Historic England technical guidance on lime mortars
The Llandudno Coastal Factor
A chimney on a north or west-facing Llandudno elevation takes the full force of salt-laden Atlantic wind. That erodes mortar 2–3 times faster than on a sheltered inland stack. Properties on the promenade, Marine Drive and the exposed seafront terraces need their stacks inspected every 10 years as a minimum — we have attended emergency make-safes where eroded flaunching left pots loose enough to be a danger, all avoidable with a routine inspection.
Flaunching, Cowls and Capping
- Flaunching — the weathered mortar fillet around the pots; renewed in lime mortar to shed water.
- Cowls — fitted to stop rain, birds and downdraught entering a working flue.
- Capping — closing off a disused flue while keeping it ventilated to prevent internal damp.