Lead Work in Diss

How we handle lead work

Lead Work in Diss and the Surrounding Villages

Lead is the material roofers reach for when a join between a roof slope and a vertical surface needs to stay watertight for decades. You will find it around chimney stacks, where a lean-to roof meets a house wall, along parapet walls, and tucked under the edges of roof windows. When lead fails, water gets in at the exact point where the roof structure is most vulnerable, so it is one of the repairs that should not be left until the next dry spell.

We carry out lead work across Diss and the villages nearby, including Roydon.

What Lead Flashing Actually Does

Lead flashing seals the gap between a roof covering and an adjacent vertical surface. Without it, rainwater running down a chimney stack or a rendered wall would track straight into the roof void. The lead is cut into strips, dressed into the mortar joint of the brickwork (called a chase), and folded down over the tiles or slates below. A separate piece called a soaker sits under each individual slate or tile at a hip or abutment, interlocking with the courses above and below.

Lead soakers are small, folded pieces of lead slipped underneath slates or tiles at a junction. Each soaker is sized to match the gauge of the slate or tile it sits with. They are largely invisible once the roof covering is back in place, but they do the critical work of directing water away from the timber substrate beneath. A common problem is soakers being left out during a re-roofing job to save time, which only becomes apparent when a leak develops months later.

Step flashing is used where a roof slope runs alongside a wall at an angle, for example at the side of a chimney or a dormer cheek. Each step piece interlocks with the course of tiles below it, so the whole assembly moves with the building rather than cracking away from it. Cover flashing, sometimes called cap flashing, then overlaps the step flashing from above and is tucked into the mortar chase.

Why Lead, and Not Something Cheaper?

Lead has been used on British roofs for centuries because it is malleable, self-healing to minor scratches and extremely long-lived when installed correctly. Code 4 and Code 5 lead (the grades most commonly used on domestic roofs) are the right choice for chimney flashings and valley gutters respectively. Proprietary self-adhesive flashing tapes are a temporary fix at best. They become brittle in frost and lose adhesion in heat, and a roofer who reaches for tape rather than lead on a permanent repair is not doing you a favour.

The British Standard for milled lead sheet (BS EN 12588) sets out minimum thicknesses for different applications. Code 3 is typically used for soakers, Code 4 for stepped and cover flashings, and Code 5 or 6 for valleys and parapet gutters. Using undersized lead to cut costs is a false economy; it moves too much with thermal expansion, splits at the folds and fails early.

What Goes Wrong with Lead Flashings

Most lead failures fall into a handful of categories:

• Mortar fillets used instead of lead at chimney abutments. A mortar fillet cracks away from the brickwork as the building moves, sometimes within a few years of being laid.
• Lead that has been dressed out too far from the wall, leaving a gap for wind-driven rain to get behind it.
• Old lead that has thinned over many decades until it splits along the dressed fold.
• Poorly pointed mortar chases that allow the lead to drop out of the wall.
• Thermal splitting, where lead has been cut in lengths longer than 1.5 metres without an expansion joint, causing it to crack at the fold as it moves with temperature changes.

Older properties often have chimneys that have not been touched since they were first built. The lead may look acceptable from ground level but be paper-thin or cracked at the back where it is hardest to see. A proper inspection means getting on the roof, not just looking up from the garden.

Chimney Lead Work

A chimney stack is the most demanding environment for lead on a domestic roof. It projects above the roof covering, catches wind from every direction and is subject to more movement than the rest of the structure. A complete chimney lead job involves front apron flashing, two sets of stepped and cover flashings on the sides, and a back gutter behind the stack. The back gutter is the piece most often bodged; it needs to be deep enough to carry rainwater clear of the stack without damming up behind it.

If a chimney is no longer in use, capping it with a lead cover or a ventilated cap is worth considering at the same time as the flashing work. A redundant pot left open collects rainwater that then sits in the flue and accelerates the deterioration of the mortar courses.

Valley Gutters

Where two roof slopes meet at an internal angle, the junction is called a valley. Open lead valleys are lined with Code 5 or Code 6 lead and carry significant volumes of water during heavy rain. Blocked or split valley gutters are a common cause of serious water damage because the failure point is often hidden under the tiles on both sides. Replacing a valley gutter involves stripping tiles from both slopes, fitting new lead dressed over a sound timber substrate, and relaying the tiles. The job is straightforward but it needs to be done correctly to avoid creating new problems at the tile edges.

What Lead Work Costs

Lead flashing repair around a chimney stack in Norfolk typically costs between £200 and £600 depending on the size of the stack, the amount of lead to be replaced, and the ease of access. A full valley gutter replacement on a standard semi-detached house generally runs from £400 to £900. Lead is priced by weight and the cost of the metal itself fluctuates with commodity prices, so any figure given at survey may differ from one given six months earlier or later. These are typical current ranges, not fixed prices, and the right figure for your property will depend on what the inspection reveals.

Lead flashing around a standard chimney stack on a domestic roof in Diss typically costs between £250 and £500 for a full replacement, with valley gutter work ranging from £400 to £900 depending on length and access.

Repairs or Full Replacement?

Old lead that has simply dropped out of its mortar chase can often be re-pointed and re-dressed rather than replaced, provided the lead itself is still in sound condition. If the lead has split, thinned or been patched repeatedly with tape, full replacement is the more cost-effective answer because partial repairs to failing lead tend to leak again within a season or two. We will tell you honestly which applies to your roof.

For older properties around Diss, it is also worth checking whether the pointing on the chimney stack itself needs attention at the same time. Repointing a stack while the scaffold or ladders are already in place costs far less than returning for a second visit.

Get a Lead Work Survey in Diss

If you have a damp patch on a chimney breast, water staining around a roof window, or you simply have not had the flashings checked in many years, call us to arrange a roof survey. We cover Diss and the surrounding area, including the villages of Roydon and Long Stratton. We will tell you what we find and what it will cost to put right before any work begins.