Lead Work in Cambourne

Expert Lead Work
in Cambourne

Why Lead Flashings Matter

Lead flashings are the seals fitted where a roof meets a vertical surface. Around chimney stacks, along dormer cheeks, at parapet walls, and where a flat roof butts up against a house wall: these are the junctions that keep a roof genuinely watertight. When they fail, water finds the gap and works its way into the roof structure, often travelling some distance before it shows up as a damp patch indoors.

Lead has been used in roofing for centuries because, properly installed to the right Code specification, it outlasts almost everything else. A correctly fitted lead flashing on a chimney should last several decades without needing attention. The problems arise when the original installation was poor, when the lead is too thin, when the fixings are wrong, or when the mortar chase holding the top edge has cracked open and let water behind.

Repair or Replace: How to Think About It

This is the decision most homeowners find hardest, because the wrong answer in either direction costs money. Replacing sound lead wastes money; repairing failing lead that's near the end of its life stores up a problem for a few years at most. Here is how to think it through.

When Repair Makes Sense

A lead flashing can be repaired rather than replaced when the lead itself is structurally sound and the correct Code thickness, but a specific section has lifted, cracked, or pulled away from the wall. Common repair scenarios include:

• A step flashing that has lifted at one end because the lead clip has corroded or pulled out. The lead itself is fine; the fixing needs replacing and the flashing re-dressed.
• A mortar chase that has cracked and opened, letting the flashing drop away from the wall. The fix here is re-cutting the chase and repointing the lead back in, not replacing the lead.
• A small split or pinhole in an otherwise sound section of lead. Lead can be patched using a compatible lead patch dressed flat and soldered or bossed in by hand, provided the surrounding material is solid.
• A front apron flashing that has slipped slightly down the roof slope. If the lead is not cracked or corroded, it can often be re-dressed back into position and re-fixed.

In each of these cases, repair is the right answer: it addresses the failure without throwing away serviceable material.

When Replacement Is the Correct Call

There are situations where trying to repair lead is a false economy, and a good contractor will tell you honestly which one you're looking at.

• The lead is the wrong Code. If the existing flashings were laid in Code 3 lead where Code 4 or 5 should have been used, no amount of re-dressing will make it last. Thin lead cracks, splits and eventually just perforates. Replacement is the only sensible option.
• The lead is heavily corroded or pitted. Lead corrodes slowly, but very old lead on older properties can become brittle and pitted throughout, not just at one point. Patching pitted lead in multiple places is neither cost-effective nor durable.
• The back gutter behind a chimney has been bodged or is missing. A sealant patch or makeshift cover over a chimney's back gutter is not a repair. The back gutter needs to be properly formed in lead. If the existing installation never had one, or it was substituted with sealant, a full replacement of that section is needed.
• A previous repair has made the underlying problem worse. Mastic or sealant applied over a failing flashing traps moisture, accelerates corrosion of any ferrous fixings, and makes the subsequent proper job harder. If this is what you're looking at, expect a replacement rather than another patch.
• The flashing has moved so far that re-dressing would put too much stress on the lead. Lead that has been displaced significantly can crack when it is dressed back. A contractor should assess this before attempting to re-use it.

What a Proper Lead Work Job Involves

Whether you are repairing or replacing, the standard of work matters. Lead is cut and dressed by hand on site to fit the specific geometry of your chimney, dormer or abutment. It's not an off-the-shelf product; every job is slightly different. The lead is fixed using lead tacks or clips at regular intervals to allow for thermal movement. Lead expands and contracts significantly with temperature changes, and flashings that are rigidly fixed crack at the fixing points over time.

The top edge of the flashing sits in a cut chase in the mortar joint or brick joint and is then pointed with mortar to seal it. The quality of this pointing matters as much as the quality of the lead itself. If the pointing is done badly or the wrong mortar is used, the chase opens up and the whole thing lifts again.

On a chimney, a complete lead work job addresses the front apron, the two side step flashings (with soakers under slates or tiles at each course), and the back gutter. All four sections matter; a chimney with three good flashings and a failed back gutter will still leak.

Typical Costs for Lead Work

Lead work on a standard chimney in this part of Cambridgeshire typically costs in the range of £300 to £700, depending on the size of the stack, how many flashings are involved, and access. A full chimney re-lead on a larger or more complex stack will be at the higher end or above. Individual repairs to a single lifted flashing or re-chasing and pointing can be considerably less, often in the £150 to £300 range. Any quote should set out clearly which elements are included.

The cost of lead itself has risen in recent years, which is why some contractors substitute thinner lead or use proprietary flashings. Ask specifically what Code of lead is being used; if a contractor can't tell you, that's a significant warning sign.

Other Roof Types Where Lead Is Used

Lead is used on both pitched and flat roof sections across Cambridgeshire. On slate roofs and plain tile roofs it appears as step and cover flashings, soakers and aprons. On flat roofs it is used at upstands and abutments, often alongside felt or EPDM rubber membranes. The lead at these junctions needs to be properly integrated with the flat roof system; a poorly formed lead upstand is one of the most common causes of leaks at a flat roof edge.

Zinc and copper are used in some heritage and contemporary applications, but lead remains the standard material for flashing work on the great majority of domestic roofs, and rightly so: it is malleable enough to fit complex shapes and, at the correct Code, outlasts most alternatives.

Cambridge Roofers Serving Cambourne and Nearby

We work on lead flashings across Cambourne and the surrounding area, including Cambridge, Girton, Histon, St Ives, and Over. If you're not sure whether your flashings need repair or replacement, call us to arrange a proper inspection. We'll tell you honestly what you're looking at and what the options are.