If the lead on your roof in Lakenheath is starting to show its age, catching it early is the difference between a small repair and a much bigger job.
Lead is used wherever two surfaces on a roof meet and need a watertight seal. That includes chimney flashings, valley gutters, bay window abutments, dormer cheeks, parapet copings and the joints around soil pipes or rooflights. Where slates or tiles end and a wall or stack begins, lead is almost always what keeps the water out.
A proper lead installation means cutting the lead to the correct code (thickness) for the location, dressing it carefully to the profile of the roof, and fixing it so it can expand and contract with temperature changes without cracking or lifting. Step flashings, soakers and cover flashings all need to be formed correctly and pointed in where they meet masonry. Cutting corners on any of these steps is how lead work fails prematurely.
Lead rarely fails without giving some warning first. The problem is that the signs are easy to miss or misread, especially from ground level. Knowing what to look for means you can act before water finds its way into the roof structure or the rooms below.
Lead expands and contracts with heat and cold. Over many years, if it was laid in pieces that are too long, or if the original installation did not allow enough movement, the surface develops fine cracks. These cracks start shallow but deepen over time. Once they go all the way through the sheet, water gets in. You may see a pattern of fine lines across the surface of the lead - this is called crazing, and it is a sign the material is fatigued and approaching the end of its life in that section.
A flashing that has pulled away from the wall or lifted at the edge is one of the most visible warning signs. Wind gets under loose lead and works it further away from the surface over successive seasons. Once there is a gap, rain blows straight in. Look at the junction between your chimney and the roof slope - if you can see daylight or a clear gap where the lead meets the brickwork, that needs attention promptly.
Lead flashings are typically held into a mortar joint in the brickwork. The mortar is raked out, the lead is tucked in, and fresh mortar seals it. When that pointing dries out, shrinks or falls away, the top edge of the flashing becomes loose and water runs behind it. A common problem is that the mortar was never raked deep enough in the first place, so the lead was never properly gripped. From a distance this can look fine until a windy or wet spell exposes it.
A damp patch on a ceiling near a chimney breast, or brown staining on a wall below a parapet, often points to a lead failure rather than a slipped tile. Water that gets in at a flashing can travel some distance before it shows itself indoors, which means the stain does not always appear directly beneath the fault. If you have had a ceiling repaired and the damp keeps coming back, the lead is a logical place to investigate.
Lead develops a natural grey-green patina over time - that is normal and actually helps protect the surface. But heavy streaking of white or green deposits running down roof tiles or stonework below a lead detail can mean the lead is shedding more than it should, or that water is running in a direction it was not designed to. It is worth getting eyes on any lead that is leaving noticeable staining on the roof surface below it.
In older lead work you may see an obvious split, a pinhole or even a section that has been crudely patched with sealant or bitumen paint in the past. Sealant-based repairs on lead are a temporary fix at best. The sealant cracks and peels within a few years, and the underlying lead continues to deteriorate. If you can see evidence of a previous patch repair, the lead in that area probably needs proper assessment and likely replacement.
Age is the most straightforward cause. Lead has a long service life - typically 60 to 100 years when correctly installed - but a lot of the lead on older properties was put on decades ago and is simply reaching the end of that span. However, poor original installation shortens that lifespan significantly.
Oversized pieces are a common installation error. Lead moves with temperature - on a hot summer day it expands, in winter it contracts. If a section is too long or too wide for the fixing method used, that repeated movement causes fatigue cracks. The correct approach is to use shorter bays with proper drips and rolls between them, allowing each section to move independently.
Inadequate support beneath lead valleys also causes problems. If the timber boarding or underlay below the valley has deteriorated, the lead above it can deform, hold standing water and eventually fail at the low points where water pools.
Thermal movement is a particular issue for lead on south-facing slopes, which experience a larger temperature range. Lead on a sunny elevation works harder than lead on a shaded one and may need attention sooner.
Lead sheet is sold in different thicknesses, referred to as codes. Code 3 is the thinnest commonly used in roofing and is appropriate only for soakers. Code 4 and Code 5 are used for flashings, with Code 5 being preferred for wider or more exposed applications. Valleys and gutters typically call for Code 6 or heavier. Using an underweight code in a demanding position is a false economy - it will fail faster and give you less time between jobs.
When getting any lead work done, it is reasonable to ask which code is being used and why. A roofer should be able to tell you without hesitation.
For a flashing repair, the old mortar pointing is raked out, the existing lead is checked. If the lead itself is sound and just the pointing has failed, re-fixing and re-pointing may be sufficient. If the lead is cracked, too short or the wrong code, it needs to come out and be replaced properly.
New lead is cut to the right length and code, dressed to the profile of the tiles or slates using a bossing mallet or dressing tool, and tucked at least 25mm into the mortar joint. It is then fixed with lead clips and the joint is pointed with an appropriate mortar or leadmate-style sealant. The lead should sit flush and tight against both the roof surface and the masonry, with no gaps visible.
For valleys, the boarding is checked before new lead goes down. Any soft or rotten timber is replaced. The lead is laid in bays with proper drips between them to allow for movement, and the edges are dressed under the adjacent tiles or slates to a consistent margin.
A straightforward chimney flashing replacement in Lakenheath typically costs in the region of £300 to £600 depending on the size of the chimney stack and how much lead is involved. A lead valley replacement on a standard semi-detached roof generally falls between £400 and £900. Bay window abutment flashings are usually at the lower end of this range unless the bay is large or the access is difficult. These figures are a guide - the actual cost depends on the condition of the existing brickwork, the pitch of the roof and what is found when the old lead comes off.
We cover Lakenheath and the surrounding villages for all lead work, from a single lifted flashing to a full valley and chimney replacement. If you have spotted any of the warning signs above, or you have had a persistent damp problem that has not been traced to an obvious source, it is worth having the lead inspected as part of any roof check.
Call us to arrange a roof survey and we will give you a straight assessment of what the lead is doing and what, if anything, needs doing about it.
No obligation · We usually respond within 2 hours
Storm damage, active leak, damaged ridge - we aim to be on-site within 24 hours.
