Lead Work in Brandon - Repair or Replace? Making the Right Call

Expert Lead Work
in Brandon

What Lead Work Is and Where It Is Used

Lead is the traditional material used to waterproof the junctions on a roof: around chimneys, where a roof meets a wall, in valleys between two roof slopes, and as soakers beneath individual tiles at abutments. Properly fitted lead sheet meeting BS EN 12588 can last 50 years or more. The problems arise when lead was fitted badly in the first place, when it has reached the end of its natural life, or when an earlier repair has failed and the damage has been allowed to worsen.

We carry out lead flashing, valley and soaker work from our base in Bury St Edmunds, covering Brandon and the surrounding area. All our lead work is hand-dressed using traditional techniques, not pre-formed sections pushed into place.

The Repair Versus Replace Question

This is the question most homeowners face once a roofer has had a look at their lead. The honest answer is that it depends entirely on what is causing the failure - not on the age of the lead alone and not on a rule of thumb. Here is how to think through it.

When Repair Makes Sense

Repair is often the right answer when the lead itself is structurally sound but a joint or fixing has failed. The most common scenario is a step flashing that has pulled out of its mortar joint. The lead sheet may be in perfectly good condition; the problem is simply that the tack or clip holding it in the chase has corroded, or the mortar around it has cracked and let the flashing lift. Re-fixing and repointing can restore a watertight joint without replacing a single piece of lead.

A minor split or pinhole crack caused by a stone or falling debris is also repairable if the surrounding lead is still in good condition and has not started to fatigue. A skilled roofer can patch this properly using compatible lead sheet and an appropriate fixing technique, though it is worth noting that a patch on old lead may outlast the surrounding material - so this only makes sense if the rest of that lead has reasonable life left in it.

As a rough guide, if the lead is less than 25 to 30 years old, has not started cracking across the body of the sheet, and the failure is clearly localised, repair is likely to be cost-effective. A straightforward repair to a chimney flashing might cost £200 to £500 depending on the scale of work and access requirements.

When Replacement Is the Better Option

Replacement becomes the right answer in several situations, and a good roofer will tell you which applies rather than automatically pushing for the more expensive job.

• Fatigue cracking across the body of the sheet. Lead expands and contracts with temperature changes. If it was dressed in sections that were too long, it cracks over time - this is called thermal fatigue. Once cracking is widespread, patching is a short-term fix at best. The sheet needs to come off and be replaced in correctly sized sections.
• Lead that is thinning at the bends. Poorly dressed lead can be physically thinned where it was bent sharply without proper support. These thin spots will eventually crack. You can sometimes see them as bright, polished lines across the surface of older lead.
• Previous repairs that have failed. If sealant has been applied over old lead and that sealant has now cracked and lifted, the lead underneath is almost always in poor condition too. Stripping back and starting again is usually more economical than another layer of temporary repair.
• Lead that is 40 or more years old and showing multiple failure points. At this age, even if one area is repaired, the surrounding lead is likely to fail soon. Replacing it all at once is cheaper than returning to the same roof every two or three years.

A full chimney flashing replacement on a typical detached house - apron, step flashings and back gutter - typically costs in the region of £350 to £800, depending on chimney size, access and how much repointing is needed. A valley replacement on a larger roof can run from £600 to £1,200 or more. These are not small numbers, but they are far less than the cost of prolonged water ingress into a roof structure or ceiling.

Questions to Ask Before Agreeing to Either Option

Whether the recommendation is repair or replacement, you are entitled to a clear explanation. Ask your roofer to show you - from the roof if possible, or in photographs - exactly where the failure is and what is causing it. The following questions are worth putting to anyone you are considering:

• Is the lead itself cracked or fatigued, or is the fixing the problem?
• If you repair it, what is the realistic lifespan of that repair given the age of the surrounding lead?
• If you replace it, what code of lead will you use, and how will the sections be jointed?
• How will the new flashing be fixed into the wall - will you cut a proper chase into the mortar joint?
• Will I get a written price before you start?

The Danger of the Sealant Patch

A common temporary fix is to paint bitumen-based sealant over failing lead. It stops the leak briefly but it does not address why the lead failed, it prevents the metal from moving naturally with temperature, and it makes proper assessment much harder the next time someone looks at the roof. If a roofer suggests sealant as the primary fix for a leaking flashing, ask why they are not addressing the underlying cause.

What Good Replacement Lead Work Looks Like

New lead flashings should be hand-dressed to fit the profile of the tiles or slates, fixed with lead tacks or clips into a proper chase cut in the mortar joint, and dressed in sections no longer than the code-specific maximum to allow for thermal movement. Code 4 or Code 5 lead is the norm for chimney and valley work. The finished joint should be pointed with fresh mortar or an appropriate weather-resistant sealant - not filled with expanding foam, not left open and not sealed over with bitumen paste.

If you have a leak around a chimney, valley or wall abutment in Brandon, get a roofer to look at it before the damage spreads. We will tell you honestly whether repair or replacement is the right call for your specific situation, and give you a clear written price before any work starts.