Lead work is one of the most skilled trades in roofing, and Mildenhall Roofers carries it out properly in Eriswell and the surrounding villages.
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Lead work covers several distinct jobs on a roof: flashing at abutments where a roof meets a wall or chimney, valley linings where two roof slopes meet, soakers behind tile courses, and flat roof coverings dressed entirely in lead. Each of these requires the lead to be cut, shaped and dressed by hand to the correct Code thickness, then properly fixed. No two installations are identical because roof pitches, masonry profiles and junction angles vary from house to house.
When lead work fails, it usually does so slowly. Water finds a gap at a flashing edge, works its way down behind plaster or into a ceiling void, and the first visible sign inside can appear weeks after the original ingress point. That delay makes it harder for homeowners to trace the source without a proper inspection. Getting lead work right the first time is far more cost-effective than remedying water damage later.
Chimney flashing is the most common lead work job on a domestic roof. A chimney stack rises through the roof slope and intersects with the tiles or slates at multiple angles. A properly flashed chimney uses stepped flashing up the sides, a back gutter behind the stack, and a front apron below it. Each piece is cut to lap correctly over the next, and chased into the mortar joints so rainwater cannot track back behind it.
Valley gutters run from the ridge down to the eaves where two adjacent roof slopes meet. A lead valley is one of the most durable options available, but only when it is formed to the right Code, has adequate width for the expected water flow, and is dressed with proper stop-ends at the bottom. A valley that is too narrow, or where the lead has been folded up short at the sides, will overflow in heavy rain.
Soakers are small individual pieces of lead fitted behind each course of tiles or slates at an abutment. They are not visible once the tiles are laid, but without them the flashing above cannot do its job properly. Soakers are sized to the gauge and lap of the tile being used, which is why lead work cannot simply be copied from one roof to another without measuring up first.
Flat roof areas covered in lead are less common than felt or EPDM rubber systems on domestic properties, but they do appear on bay tops, dormers, and small extensions. A lead flat roof is dressed in bays with proper drips between each bay to allow the lead to move with temperature changes without splitting or creeping. The bays must not be too large or the movement stress will crack the lead over time.
Lead sheet is graded by Code, which refers to its thickness and weight. The higher the Code, the thicker and heavier the lead. For roofing in the UK, the most commonly used Codes are Code 3, Code 4, Code 5 and Code 6. Choosing the right Code for the job is not a matter of preference; it is governed by the application and by the recommendations set out in the Lead Sheet Association guidance.
Using an undersized Code is one of the most common causes of premature lead failure. Code 3 fitted to a chimney back gutter, for example, will crack within a few years because the thermal movement is too great for the thickness available. If you are getting quotes for lead work, ask which Code is being specified for each part of the job and why. Any competent roofer should be able to answer that without hesitation.
Lead is not the only material used for flashing and valley work. Alternatives include aluminium, zinc, copper, and mortar-based solutions such as sand and cement fillets. Each has genuine advantages and genuine drawbacks, and the right choice depends on the specific situation, the budget, and what the original roof design calls for.
Pros: Lead is the traditional standard for a reason. It is highly malleable, which means it can be dressed accurately into complex profiles without cracking. It bonds well to masonry surfaces and, when correctly installed, is extremely durable. Lead weathers to a stable grey patina that requires no painting or coating. A properly installed lead flashing on a chimney, fitted to the correct Code and chased in properly, can last several decades without attention.
Cons: Lead is expensive relative to the alternatives, both as a material and in the skilled labour required to work it properly. It is also heavy, which matters on some structures. Lead can be subject to theft on accessible roofs, though this is less of an issue on steep domestic pitches than on low-level commercial roofs. It is also vulnerable to corrosion from certain mortars and from lime-rich run-off; patination oil is applied during installation to slow this process.
Pros: Aluminium flashing strip, often sold as a self-adhesive product, is cheap and quick to fit. It is lighter than lead and will not be stolen. For a very small repair in an inaccessible position, it can provide a short-term fix.
Cons: Aluminium does not dress as cleanly as lead around complex shapes. Self-adhesive versions rely on adhesive bond, which deteriorates with UV exposure and temperature cycling. Aluminium flashing is not appropriate as a long-term replacement for properly dressed lead on a chimney or valley. A roof sold as "lead-flashed" that turns out to have aluminium strip behind the tiles is not the same standard of work.
Pros: Zinc is durable, lighter than lead, and works well on modern or contemporary roof designs where a different aesthetic is wanted. It is resistant to atmospheric corrosion and does not suffer from the thermal creep issues that lead can have if installed in oversized bays.
Cons: Zinc is harder to work than lead and less forgiving when dressing into tight profiles. It costs more than lead in material terms. It is relatively uncommon on traditional domestic roofs in the UK, so fewer roofers have extensive experience with it.
Pros: Copper is extremely durable and visually distinctive, weathering to a characteristic green patina over time. It is used on high-specification or heritage buildings where appearance and longevity are the priorities.
Cons: Copper is significantly more expensive than lead and the run-off from copper can stain adjacent masonry. It is not a common choice for standard domestic lead work in this area, and the pool of roofers experienced in working it is smaller.
Pros: Cement fillets at abutments are cheap and quick to apply. They require no specialist skills beyond basic brickwork.
Cons: Cement fillets crack as the roof structure and masonry move seasonally. They are not a like-for-like substitute for lead flashing. A cement fillet at a chimney abutment is a temporary measure at best and frequently the first thing to fail when a roof starts leaking. Where you see a mortar fillet where lead should be, budget for replacement rather than repair.
Badly installed lead is more common than it should be. Flashings chased too shallowly into mortar joints will pull out when the lead expands in summer heat. Lead dressed over too large a bay without a proper drip will split along stress lines within a few years. Soakers omitted because they slow the job down leave the flashing doing work it cannot do alone.
A lead flashing that has been simply pushed into a raked-out joint and pointed with mortar, rather than secured with lead wedges and then pointed, will fail within a short time. The joint opens slightly as the building moves, the mortar pointing cracks, and water tracks straight in. This is not a difficult repair if caught early, but it requires re-doing the flashing properly rather than just re-pointing over it.
Old lead that has reached the end of its life will show fatigue cracking, usually in a pattern that follows the direction of thermal movement. This kind of cracking cannot be repaired by patching. The lead section needs to be replaced. Patching fatigued lead with flashing tape or sealant extends the problem rather than solving it.
Before any lead is cut, the existing situation needs to be understood: what Code lead is already there (if any), how the existing flashing relates to the tile or slate gauge, where the water is actually entering. Replacing lead without understanding the cause of the original failure risks repeating it.
Existing mortar and old lead are removed back to clean masonry. The chase is cut or raked to sufficient depth, typically at least 25 mm, to accept the new flashing securely. The lead is cut to length, dressed to the profile of the surface, and fixed with lead wedges driven into the chase at regular intervals before the joint is pointed with a flexible mortar or mastic. The dressing should follow the exact profile of the underlying surface without gaps or bridging.
At a valley, the old lead or alternative material is stripped, the valley boards are inspected and replaced if necessary, and the new lead is dressed and fixed in sections with proper overlapping joints and stop-ends. Tiles or slates are cut and re-fitted to the correct clearance from the valley centre line.
Lead work generates debris: old lead, broken tile off-cuts, old mortar. A tidy job means this is cleared from the roof and gutters before the work is signed off. Leaving debris in gutters causes blockages and roof staining.
Lead work pricing in the UK varies considerably depending on the scope, access difficulty and Code of lead specified. As a general guide, chimney flashing replacement using Code 4 or Code 5 lead typically costs between £300 and £700 for a standard domestic chimney stack, depending on size and access. Valley re-leading in Code 5 or Code 6 is generally priced by the metre and can range from roughly £80 to £180 per linear metre. Flat roof lead on a small bay top or dormer varies by area but expect prices in the range of £100 to £200 per square metre, reflecting both the material weight and the skilled labour involved.
These are indicative ranges only; the actual price for a specific job in Eriswell or nearby will depend on a proper assessment of the roof. Scaffolding or access equipment adds cost that should be quoted separately and clearly. Any quote that does not specify the Code of lead being used, or the method of fixing, should prompt you to ask before accepting.
Mildenhall Roofers carries out lead flashing, valley and flat roof lead work in Eriswell and the wider area around Mildenhall. All lead is dressed by hand to the specified Code and properly secured with lead wedges before pointing. We work on chimney stacks, abutment flashings, tile and slate valleys, and lead bay tops on dormers and extensions.
If you have a leak that you suspect is coming from a flashing or valley, call us to arrange a roof survey. We will identify the source, explain what needs to be done, and give you a clear, itemised quote that specifies the Code of lead and how it will be fixed.
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