Chimney Repointing Godalming

Why Chimney Repointing Matters in Godalming

Godalming has more chimney stacks per property than most Surrey towns, thanks to its concentration of Victorian, Edwardian and pre-war housing. Every chimney is exposed to the full force of the weather — wind, rain, frost and thermal cycling — and the mortar joints bear the brunt. In the Wey Valley's persistently humid climate, mortar erosion is 20–30% faster than in drier parts of the county.

Lime Mortar vs Cement — Getting It Right

The most important decision in chimney repointing is mortar type. Modern cement mortar is appropriate for post-1920 brick chimneys. But for older chimneys — and particularly for Bargate stone chimneys around Charterhouse, Frith Hill and parts of the High Street — cement is actively harmful. Cement is harder than Bargate stone and traps moisture inside the masonry, causing spalling damage that is irreversible. We use NHL 3.5 or NHL 5 Natural Hydraulic Lime mortar on all pre-1920 and Bargate stone chimneys.

Flaunching

Flaunching is the mortar slope around the base of chimney pots. It sheds rainwater away from the pot opening and prevents water tracking down into the flue. Cracked flaunching is one of the most common causes of chimney damp — and one of the cheapest to repair. We reform flaunching in mortar matching the repointing specification.

Cowls and Capping

Unused flues should be capped or fitted with cowls to prevent rain entry while maintaining ventilation. A vented cap costs £80–£150 fitted. For chimneys no longer in use, capping eliminates ongoing maintenance costs while preserving the stack for aesthetic and structural purposes — important in the Conservation Area where chimney removal may need consent.

Bargate Stone — Godalming's Specialist Challenge

Bargate stone chimneys are unique to the Godalming area. The warm honey-coloured sandstone was quarried locally until World War II and is a defining architectural feature. We regularly repair damage caused by previous incorrect cement repointing — cutting out the cement, cleaning joints, and repointing in lime mortar that allows the stone to breathe. This specialist work costs more than standard repointing but prevents the irreversible destruction of irreplaceable stone.

How to Tell If Your Chimney Needs Repointing

You can assess your chimney's mortar condition from ground level with binoculars. Look for: gaps where mortar has fallen away entirely, crumbly or sandy mortar that has lost its binder, cracks running along or through mortar joints, dark staining below joints (water tracking through rather than off), and any patches of obviously different-coloured mortar from previous partial repairs. If you can see any of these signs, the chimney is allowing water into the masonry — and in Godalming's wet climate, that water causes damage faster than in drier locations.

Inside your home, check walls adjacent to the chimney for damp patches — particularly after prolonged rain. A failing chimney acts as a funnel, channelling rainwater through eroded joints and delivering it into the internal wall structure. In severe cases, this causes plaster damage, mould growth, and staining that requires redecoration after the chimney is repaired.

The Repointing Process — Step by Step

Repointing is methodical work that cannot be rushed. We rake out existing mortar to a depth of 15–20mm using hand tools (never angle grinders on Bargate stone or soft brick — the vibration damages the masonry). Each joint is brushed clean of loose material and debris. The masonry is dampened to prevent it drawing moisture from the new mortar too quickly. Fresh mortar is pressed firmly into each joint using pointing keys, then finished to match the original joint profile — flush, recessed, or weather-struck depending on what the building had originally.

On a standard chimney stack, repointing takes a skilled operative 4–8 hours depending on stack size and mortar type. Lime mortar takes longer than cement because it requires more careful application and must not be worked in freezing conditions. We schedule lime mortar chimney work between April and October to ensure proper curing.

Flaunching, Cowls and Caps — The Complete Chimney Service

We rarely repoint a chimney without also addressing flaunching (the mortar slope around pot bases), pot condition, and capping or cowl requirements. Doing all chimney work in one visit maximises the value of the scaffold or ladder access and ensures the entire chimney is weathertight when we leave — not just the joints.

Flaunching renewal costs £100–£250 per chimney and is almost always needed when repointing is due. Chimney cowl installation costs £80–£150 per pot and is recommended for all unused flues to prevent rain entry and bird nesting. Chimney caps (for permanent flue closure) cost £100–£200 and eliminate all ongoing maintenance costs for that flue while maintaining ventilation through the building structure. Call 01483 346 855 for a free chimney assessment.