Chimney Rebuilds in Chippenham

Expert Chimney Rebuilds
in Chippenham

Why Chimney Problems Rarely Fix Themselves

A chimney stack sits exposed on top of your roof, taking the full force of rain, frost and wind year round. Unlike most parts of your home, it has no protective layer between the brickwork and the elements. That means when something starts to go wrong, it tends to get worse with each season rather than settling down.

The critical thing to understand is that a chimney in poor condition is not just an eyesore. Open mortar joints let water into the stack, which then freezes and expands in cold weather, forcing the bricks apart from the inside. A leaning stack puts uneven load on the roof structure. Spalled or crumbling brickwork can drop onto the roof covering below, causing secondary damage that costs more to repair. Acting early is nearly always cheaper than waiting.

Warning Signs to Look For

You do not need to get onto the roof to spot several of these. From ground level, look at the stack and note anything unusual before you call us.

• A visible lean or tilt - the stack should rise perfectly plumb. Any lean, even a slight one, suggests the mortar courses at the base have failed or the roof timbers supporting the breast have moved.
• Staining on the chimney breast inside the house - brown or yellow tide marks on the plaster around a fireplace or on a chimney breast in an upstairs room almost always mean water is getting in somewhere above roof level.
• White powder (efflorescence) on the brickwork - this white crystalline deposit is a sign that water has been passing through the bricks and evaporating out of the face, carrying salts with it. It tells you the brickwork is saturated.
• Loose or missing mortar joints (open jointing) - gaps between the bricks where the mortar has fallen out. This is one of the most common causes of water entry into a chimney stack.
• Cracked or collapsed flaunching - the flaunching is the sloped mortar bed at the top of the stack that holds the pot in place. When it cracks, water sits in the joint and attacks the top courses of brickwork. A pot that rocks or sits at an angle is a sign the flaunching has gone.
• Spalled brickwork - bricks where the outer face has broken away, leaving a rough or pitted surface. Spalling is caused by water getting into the brick and expanding when it freezes. Once bricks spall, they absorb water even faster.
• Damaged or poorly dressed lead flashings - the lead where the chimney meets the roof slope seals the joint between the two. Cracked or lifted lead lets water run behind the stack and into the roof space. Flashings deteriorate separately from the stack itself, but they are always checked at the same time.

What Causes Chimney Stacks to Deteriorate

Frost is one of the biggest factors. Water gets into a joint or a porous brick, freezes overnight, and the expansion forces the material apart. Repeat this over several winters and even well-built brickwork begins to break down. Stacks that face prevailing wind and rain are usually the first to show problems, and exposed positions on the roof ridge accelerate the process.

Mortar mix is another factor people overlook. Older stacks were built with lime-based mortars, which are slightly flexible and allow for very small amounts of movement. If those joints are repointed with a hard cement mortar - which is done by well-meaning but inexperienced contractors - the rigidity of the cement causes the softer original bricks to crack rather than the joint. Matching the mortar to the age and type of brick matters.

Lack of use makes things worse in some cases. A chimney that is no longer used for a fireplace has no warm air rising through it to carry moisture away. Damp can sit in an unused flue for long periods, attacking the stack from the inside as well as the outside. Fitting a pot cover or capping the flue properly is worth doing even on a decorative chimney.

Poorly maintained or missing lead flashings at the base of the stack mean water that should run off the roof instead tracks behind the stack and into the roof space. This can cause damp patches on ceilings or walls well away from the chimney itself, making the source hard to trace without a proper inspection.

When a Repair Is Enough and When a Full Rebuild Is Needed

Not every chimney problem requires a full rebuild from the roof line upward. A stack that is structurally sound but has deteriorating joints might only need repointing. Flaunching can be replaced on its own if the brickwork beneath it is solid. Flashings can be redressed or replaced without touching the stack.

A rebuild from the roof line is the right course when the brickwork itself has failed - when bricks are spalling or breaking apart, when the stack has moved or leaned, or when there are so many failed joints that repointing would effectively mean taking the stack apart anyway. In those cases, it is more economical and safer to take the stack down to a sound point and relay fresh courses with correct materials.

When we inspect a chimney in Chippenham or nearby, we look at the condition of every element: the brickwork, the mortar, the flaunching, the pot and the flashings. We will tell you honestly what needs doing and what can be left. If repointing is all that is needed, we will say so.

What a Chimney Rebuild Involves

All chimney work is carried out from purpose-built scaffold. This is not negotiable - working off a ladder on a chimney stack is unsafe for the roofer and leaves you with no proper access for the careful work involved. If a contractor offers to do a chimney rebuild without erecting scaffold, treat that as a warning sign.

Once the scaffold is in place, the failed courses of brickwork are carefully removed down to a solid point. The remaining stack is checked and any loose mortar cleaned back. New brickwork is laid using a mortar mix appropriate to the age and type of the existing bricks. The pot is reseated and the flaunching relaid so water sheds cleanly away from the stack. Flashings are checked and redressed or replaced as required. The scaffold is then struck and all debris cleared from the roof and surrounding area.

Chimney Rebuild Work Across the Area

Newmarket Roofers carries out chimney rebuilds across Chippenham and the wider area including Newmarket, Mildenhall, Isleham, Wicken and neighbouring villages. If you can see a problem with your chimney from the ground, or if you have had a damp patch appear near a chimney breast, call us for a chimney survey so we can give you a clear picture of what is going on.