Lead Work in Newmarket

Expert Lead Work
in Newmarket

Why Lead Work Fails - and What to Look For

Lead is the most durable flashing material available, but even well-installed lead has a lifespan. When it starts to fail, it rarely happens all at once. The deterioration is gradual, which is why so many homeowners in Newmarket are surprised to discover that water has been getting in for months before they notice a damp patch on a ceiling.

Knowing the warning signs means you can act before the leak causes serious damage to timbers, ceilings or insulation. Here is what to look for from ground level and, if you can access it safely, from inside the loft.

Visible Warning Signs on the Outside

• Lifted or peeling flashings. Lead that has pulled away from the mortar joint or the roof surface is no longer waterproof at that edge. Even a small gap is enough for wind-driven rain to force water underneath.
• Cracking or crazing. Lead expands and contracts with temperature changes. Over time, without proper detailing, this can cause hairline cracks along folds and drips. A cracked drip edge at the base of a chimney stack is a common first failure point.
• White staining (carbonate bloom). A chalky white deposit on brickwork below a flashing indicates water is running down the face of the stack rather than being directed away. It means the lead is failing at the joint.
• Mortar missing from the lead chase. Lead step flashings and cover flashings are tucked into a raked mortar joint (the chase) and held with wedges or clips. When the pointing crumbles, the lead loses its fixing and lifts in the wind.
• Corrosion or pitting. Lead can corrode where it contacts certain timbers, especially oak or cedar, or where acidic runoff from moss concentrates on the surface. Pitting reduces the thickness of the sheet and eventually causes pinhole leaks.
• Lead that has slipped or buckled. Thermal movement is normal, but if the lead has not been laid in correctly-sized bays with proper drips and rolls, it will creep downslope over time, opening gaps at the top edge.

Warning Signs from Inside the Loft

Always check the loft space after heavy rain if you suspect a flashing problem. Look for dark staining on rafters, damp or blackened felt directly below the chimney stack or dormer cheeks, and any signs of mould on timber or insulation. Water does not always drop straight down - it can travel along a rafter for a metre or more before dripping, so the wet patch inside may not sit directly below the failing lead.

A damp smell in a room near a chimney breast, even with no visible staining, is worth investigating. Slow seepage through failing lead work can saturate plasterwork without producing an obvious drip for months.

What Causes Lead Flashings to Fail

Understanding the cause matters, because fixing the symptom without the cause means the repair fails again. The most common causes of lead failure in practice are:

• Poor original installation. Lead laid in bays that are too long cannot accommodate thermal movement. The rule of thumb is that Code 4 or Code 5 lead should be laid in bays no longer than 1.5 metres. Longer bays will buckle and eventually split at the folds.
• Wrong Code of lead. Lead is graded by thickness from Code 3 to Code 8. Code 3 is too thin for most flashing applications and is sometimes used to cut costs. It wears through quickly, especially on south-facing roofs where the sun accelerates thermal cycling.
• Poorly pointed chases. If the mortar holding the lead into the brickwork has been done badly - too weak a mix, not raked deep enough, or not keyed properly - it fails within a few years and the lead lifts.
• No patination oil applied. New lead should be treated with patination oil to prevent the white lead carbonate runoff that stains brickwork and tiles. Skipping this step is a sign of rushed work.
• Bodge repairs with sealant. A bead of mastic or silicone over a failing flashing is not a repair. It holds for one or two winters, then shrinks, cracks and lets more water in than before. If you have had this done previously, the lead underneath will need proper assessment.
• Mechanical damage. Scaffolding strikes, aerial or satellite dish fittings, and foot traffic on roofs without boards can all dent, crack or dislodge lead flashings.

Where Lead Work Is Used on a Roof

Lead flashings appear at every junction where the roof surface meets a vertical element. On a typical house in Newmarket, that means the chimney stack (step flashings up the sides, a soaker or back gutter behind, and a cover flashing over the top), dormers (cheek flashings and a head flashing at the top), flat roof abutments where a flat section meets a wall, and valleys between two pitched roof slopes.

Each location has its own detailing requirements. A chimney back gutter, for instance, needs to be large enough to carry the volume of water that runs off the rear slope, and it needs an upstand high enough to cope with heavy rain without overtopping. Getting these dimensions wrong is a common cause of leaks that look like chimney flashing failures but are actually back gutter problems.

Repair or Full Replacement?

Not every failing flashing needs to be stripped and relaid. A flashing that has simply lost its pointing can sometimes be re-fixed, re-wedged and repointed if the lead itself is still sound. However, lead that has cracked through, corroded to a thin section, or been laid in oversized bays without proper drips will need to come off.

Patch repairs with lead flashing tape are suitable for very small areas - a pinhole or a minor split - but they are not a permanent solution for a flashing that has failed along its length. If more than about 20-25% of a flashing run is showing problems, a full replacement is usually better value over five to ten years.

Typical lead work repair costs for a chimney stack range from around £200 to £500 for repointing and re-fixing, rising to £600-£1,200 or more for a full strip and relay, depending on the size of the stack, access, and the extent of any associated brickwork repairs. These are rough guide figures - a proper price requires someone on the roof to assess what is actually there.

What a Proper Lead Work Job Looks Like

Good lead work is cut and dressed on site to fit the specific geometry of the roof. It is not bought pre-formed and bent into place. The lead is fixed with clips or wedges (never nails through the face), laid in correctly-sized bays, finished with a proper drip or roll at each bay joint, and pointed with an appropriate mortar mix. Patination oil is applied before the scaffolding comes down.

If you are having work done after seeing a leak, ask the roofer to show you, or photograph, the old lead that came off. You should be able to see whether it cracked, corroded or simply lifted because it was not fixed properly. That tells you whether the new installation needs to be heavier-gauge lead, shorter bays, or better fixing detail.

Lead Work Across the Cambridge Area

Lead work of this kind is needed across Newmarket and the surrounding area, including Cambridge, Ely, and neighbouring villages. Whether it is a chimney stack on a Victorian terrace, a dormer flashing on a modern extension, or a flat roof abutment, we cut and dress lead to the correct Code specification for a watertight finish.

If you have spotted any of the warning signs above, call us to arrange a roof survey so we can assess what needs doing before the next rainy spell.