If you've spotted a damp patch on a chimney breast or a persistent drip after heavy rain, faulty lead flashing in Costessey is very likely the cause.
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Lead flashing is the strip of dressed lead that seals the joint between a roof surface and any vertical element it meets: a chimney stack, a dormer wall, a parapet, a valley between two roof slopes, or the upstand at a flat roof edge. Without a properly fitted and dressed piece of lead at each of these junctions, rainwater tracks straight into the roof structure every time it rains.
We cut and dress each piece of lead on site, fitting it to the exact profile of the masonry or timber it has to seal. A competent lead job is not a matter of pressing a sheet into place and pointing over the gap. The lead has to be cut to the correct stepped or continuous profile, fixed into a chased chase in the mortar, tucked in properly at each end, and dressed tight to the surface below so there is no gap for water to enter.
Lead work in Costessey covers chimney flashings, valley gutters, dormer cheek flashings, flat roof upstands and bay window roof junctions. Each of these is a distinct job with its own method, and the skill is in reading what the roof needs rather than applying the same approach to every situation.
Most homeowners do not think about lead flashing until water is already getting in. By that point the damage can extend well beyond the flashing itself into timbers, plasterboard and insulation. Knowing the earlier warning signs means you can act before the repair bill grows.
A damp patch appearing on the chimney breast inside the house, particularly after rain, points strongly to the chimney flashing rather than the chimney pot or stack itself. The flashing wraps around the base of the stack where it meets the roof slope. When it fails, water runs down the back or sides of the stack and soaks into the brickwork from behind rather than down through the flue, so the chimney pot and cowl can look perfectly fine while water is still getting in.
If the damp patch is at the back of the chimney breast (the side facing away from the slope), the back gutter or back flashing - a wider piece of lead that sits behind the stack and channels water around it - is the most likely culprit. If the patch is to the side, check the side step flashings first.
A brown stain or tide mark on a ceiling directly below a valley or dormer is another classic sign. Valleys carry a significant volume of water from two roof slopes and the lead lining them takes a heavy load. A small split or lifted edge in a valley is enough to send water into the roof space every time it rains hard.
Dormer cheeks - the vertical side walls of a dormer window - are finished with lead flashings at the junction with the main roof. These are a known weak point on older dormers because the lead was often dressed over timber that has since moved or shrunk slightly, pulling the flashing away from the wall.
You can sometimes spot failing lead from the ground with a pair of binoculars. Look for lead that has turned a pale grey-white rather than the even dark grey of sound lead; this can indicate that the surface has started to oxidise unevenly, which is not always a problem in itself, but look more carefully for cracks running across the surface, particularly across any section that bridges a gap or a mortar joint.
Lifting at the edges - where the lead has peeled slightly away from the brickwork or the roof surface - is a more immediate sign of trouble. Once an edge lifts, wind drives rain directly underneath and the leak begins.
Many older flashings are held in place partly by mortar pointing that was tucked in over the top edge of the lead where it sits in a chase cut into the mortar joint. When this pointing fails - which it does as mortar weathers and shrinks - the top edge of the flashing is no longer held firmly, and the section below can lift or shift. You will see loose, crumbling or missing mortar at the top of the flashing if this is happening.
Raking out and re-pointing the chase is part of a proper lead flashing repair. Simply pressing the lead back and running a bead of mastic over it is a short-term fix that will fail again within a year or two.
A tell-tale sign of a previous bodge job is visible sealant or roofing compound smeared over the lead. It tends to crack and shrink within a season, and while it may stop a leak temporarily, it makes the underlying problem harder to assess and harder to repair properly. If you can see black or grey compound on your flashings, it is worth having the lead inspected rather than waiting for the sealant to fail entirely.
Understanding the cause of a failure is important because it affects how the repair should be done. Fixing the lead without addressing the underlying cause often means the problem returns.
Lead expands and contracts with temperature changes. In summer, dark lead on a south-facing roof can reach temperatures that would surprise most people; in winter the same piece shrinks back. Over many years this repeated movement causes the lead to crack, particularly across any section that is fixed too rigidly at both ends. A common problem is lead that was installed in long, continuous runs without expansion joints, so all the movement is concentrated in one spot until it cracks.
The standard guidance is to keep individual lead sections to 1.5 metres or less and to use proper fixing clips rather than nailing through the lead itself. Nailing through lead is another cause of cracking because the nail prevents movement and the lead tears around the fixings.
Lead is one of the most durable roofing materials available and a properly installed lead flashing can last several decades. But it does not last forever. Lead on older properties can develop fatigue cracks simply from decades of thermal cycling, especially if it was on the thin side to begin with. Code 3 lead (used for flashings) has a typical service life of around 60 years under normal conditions; Code 4 lasts longer. Thin lead installed on a budget decades ago may simply have reached the end of its useful life.
Houses move slightly over time, and old mortar joints shrink and crack. When the mortar holding the top of the flashing in the chase deteriorates, the flashing loses its anchorage. Similarly, if the chimney stack or dormer structure shifts even slightly, the lead that was dressed tight to it is pulled or pushed and the seal breaks.
A significant number of flashing failures come down to the original work not being done correctly. Common problems include lead that was dressed cold rather than worked with a bossing mallet, sections that were run too long without expansion allowance, back gutters that were pitched incorrectly so water pools rather than drains, and edges that were simply bent down rather than properly tucked into a chase. Identifying a poor original installation matters because the repair has to correct the underlying mistake, not just patch what has failed.
Every lead job starts with a proper inspection to identify what has failed and why. We look at the lead itself, the mortar and masonry around it, the condition of the roof surface it meets, and whether any water has tracked through into the roof structure. There is no point replacing a flashing without checking whether water has already reached the timbers or sarking felt below.
Where a flashing can be re-dressed and re-fixed, we do that rather than replace the whole section unnecessarily. Lifting the lead, cleaning up the surface, raking out the chase, re-bedding the top edge in fresh mortar and re-dressing the lead to the profile it needs is often all that is required on a flashing that has lifted but has not cracked through.
Where the lead has cracked, split or fatigued, replacement is the right answer. We cut new lead to the correct code for the application: Code 4 for most chimney flashings and valley gutters, Code 3 for light apron and step flashings on a gentle pitch. We cut and dress each piece on site to fit the exact profile of your chimney stack, dormer or valley, fix it correctly with lead clips rather than through-nails, and point the chase with fresh mortar. Every joint and end detail is dressed tight before we leave.
Lead work is priced by the job rather than a simple rate per metre, because the access requirements, the complexity of the profile and the condition of the surrounding masonry all affect the time involved. As a general guide, a chimney flashing repair on a standard semi-detached house typically costs in the range of £200 to £500 depending on how much lead needs to be replaced and whether the chimney can be reached from a ladder or requires scaffolding. A full chimney flash replacement with back gutter, step flashings and apron is likely to fall in the range of £400 to £900.
Valley gutter relining tends to cost more because of the length of lead involved and the fact that some tiles or slates usually need to be carefully lifted and relaid around the valley. A typical valley on a two-storey house might run from £500 to £1,200. Flat roof upstand and edge flashings are generally priced per linear metre, with £40 to £80 per metre being a reasonable guide for EPDM-compatible lead detailing.
These are typical UK ranges rather than fixed prices. An accurate figure needs a look at the actual job. If you are in Costessey or nearby and want us to take a look, call us and we will arrange a time to come out and give you a proper assessment.
It is tempting to reach for a tube of roofing sealant when a flashing starts to leak, and some contractors offer this as a quick fix. The problem is that sealant is not flexible enough to accommodate the thermal movement that lead handles naturally. It cracks within one or two winters, particularly on a chimney stack that heats and cools significantly. Worse, a thick bead of sealant can trap water behind it rather than channelling it away, making the situation worse over time.
A properly repaired or replaced lead flashing is the correct solution and, in most cases, the cheaper option over five years when you factor in repeated sealant applications and the water damage that accumulates while the bodge holds imperfectly.
If you can see the warning signs described above - lifting edges, crumbling mortar, cracked lead, or damp patches inside after rain - it is worth acting promptly rather than waiting until the next heavy rain confirms the problem. Water finding its way into a roof structure is not self-limiting; it follows timber grain and travels further than the entry point, so a relatively modest repair at the flashing can prevent a much larger job on the timbers, insulation or ceiling plasterboard below.
Costessey homeowners, and those in nearby towns and villages, can call us directly to arrange a lead work inspection. We will tell you honestly whether the existing flashing can be re-dressed or whether replacement is the better option for the long term.
A properly installed lead flashing using Code 4 lead typically lasts 60 years or more. Thinner Code 3 lead in a demanding position such as a valley gutter may have a shorter service life. Lead that was poorly installed or has been repeatedly patched with sealant will fail sooner regardless of its age.
Often yes. If the lead itself is sound but has lifted at the edges or lost its mortar anchorage, re-dressing and re-pointing is a legitimate repair. If the lead has cracked through or fatigued across its width, replacement of that section is the right approach. We assess each job on its merits rather than defaulting to full replacement every time.
It depends on the height and position of the work. Many chimney flashings on a standard two-storey house can be accessed safely from a ladder or with a roof ladder. Taller properties, hipped roofs, or work that requires spending a significant amount of time on the roof will generally need scaffolding for safe access. We will advise on access requirements when we assess the job.
The back gutter is the piece of lead that runs across the back of the chimney stack, where the stack meets the upper slope of the roof. Its purpose is to catch water running down the roof slope above the stack and channel it around the sides of the stack and away. A failed back gutter is a common source of damp on the upper part of a chimney breast and at ceiling level directly behind the stack.
Yes. Cracks in lead can be very fine and invisible from ground level but still wide enough to allow water ingress under pressure from driven rain. A lifting edge at the back of a chimney is also hidden from the usual viewing angle. If damp patches inside the house point to the roof, a closer inspection of the flashing is always worthwhile even if it looks intact from the ground.
We carry out lead work across Costessey and the surrounding area. Whether the job is a straightforward chimney flashing repair or a full valley reline on a larger property, the approach is the same: assess the cause, cut and dress the lead correctly on site, and leave the junction properly sealed.
Call us to arrange a lead work inspection in Costessey. We will give you a straight assessment of what needs doing and an honest price for the work.
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Call any time. Calls are answered day and night and passed straight to our roofers.
