If you have a leak around a chimney, dormer or valley in Easton, failing leadwork is the most likely cause - and the warning signs are often there long before water gets inside.
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Lead flashings are the strips of dressed metal that seal the joint wherever a roof meets a vertical surface - a chimney stack, a dormer cheek, a parapet wall, or the valley where two roof slopes meet. When they fail, water finds its way in. The frustrating thing is that by the time you notice a damp patch on a ceiling, the leak has often been running for months behind the scenes.
Knowing what to look for from ground level - or from a loft hatch - can save you from a much larger repair bill. This page explains the warning signs of leadwork failure, what causes each one, and when to call a roofer.
None of these signs on their own is proof that lead has failed, but any one of them deserves a proper look from a roofer with a ladder.
Lead is one of the most durable roofing materials available - properly installed, it can last 60 years or more. But there are several reasons why flashings fail well before that.
Every time the temperature changes, lead expands and contracts. A chimney flashing might go through tens of thousands of expansion and contraction cycles over its lifetime. If the lead was laid in sections that are too long, or without properly spaced fixings, those stresses concentrate in one place and the metal eventually cracks. Older properties with original mid-20th century leadwork are often at this point now.
The most common single cause of flashing failure is the mortar joint that holds the top edge of the lead into the brickwork. Over time, freeze-thaw cycles and general weathering erode the pointing. Once the mortar cracks, the top edge of the flashing lifts slightly and rainwater runs straight behind it and down the wall cavity. Re-pointing the mortar alone is not a proper repair - the lead itself needs to be re-dressed and re-fixed into a clean, sound raglet.
A common problem on older properties is lead that was fixed using materials or methods that are now known to be inadequate. Lead should be fixed to the correct BS EN 12588 code thickness for its location - Code 3 for soakers, Code 4 for step flashings, Code 5 for chimney back gutters and valley linings. Thinner lead, or lead that was fixed with the wrong type of clip or without a drip detail, tends to fail much sooner. If a previous repair used the wrong code, it will not last.
If a chimney stack has settled slightly, or if there is any movement in the roof structure itself, the flashing has to accommodate that movement. Lead is flexible enough to do so - if there is enough of it and it is correctly dressed. Rigid repairs using cement mortar fillet instead of lead are a common bodge that cracks and fails quickly because mortar cannot flex.
Mastic sealant or bitumen bandage applied over a failing flashing is a temporary measure at best. It addresses the symptom rather than the cause, and it often hides the problem from view, meaning the underlying lead continues to deteriorate undetected. When the sealant eventually fails - which it does, usually within a few years - the repair is often in a worse state than the original problem.
A sound repair involves stripping out the old lead completely, clearing the raglet of crumbling mortar, cutting and dressing new lead to the correct code thickness, and fixing it with the correct clips before re-pointing the raglet with a durable mortar mix. Soakers - the individual lead pieces that sit under each roof tile at a step - should also be renewed at the same time if they are original, because they are subject to the same fatigue as the visible flashings.
On chimney stacks, a proper job addresses all four sides: two step flashings up the sides, a front apron flashing at the front, and a back gutter - the most critical piece - behind the stack where the greatest volume of water collects. Cutting corners on any one of these defeats the purpose of the rest.
The sooner a leadwork problem is caught, the cheaper the repair. A flashing that has slipped but is otherwise intact can sometimes be re-fixed. One that has cracked and been leaking for two winters may have caused timber decay in the rafters or wallplate, which is a much larger job. If you have noticed any of the signs listed above on your Easton property, call us for a roof survey so we can tell you exactly what is happening and what it will take to fix it properly.
Leadwork failures rarely happen in isolation. A deteriorating chimney stack often has loose or cracked pointing on the brickwork above the flashing line as well. Valley gutters that have been leaking may have caused the felt underlay or timber boarding beneath to deteriorate. When a leadwork repair is carried out, any related issues that can be seen should be flagged so the homeowner has the full picture.
Dereham Roofers carry out lead flashing repairs and replacements across Easton and the surrounding area. When arranging a survey, make sure the roofer gets up on the roof, takes a proper look, and explains what is needed.
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Call any time. Calls are answered day and night and passed straight to our roofers.
