Lead Work in Lakenheath

Expert Lead Work
in Lakenheath

Lead as a Roofing Material - What You Are Actually Buying

Lead has been used on roofs in Britain for centuries, and for good reason. It is malleable enough to be dressed tightly around complex shapes, it bonds well with masonry, and - when correctly specified and fitted - it outlasts most other flashing materials by a considerable margin. But not all lead is the same, and the differences in thickness, fixing method and system choice genuinely affect how long the job holds up.

In the UK, lead sheet for roofing is sold in coded thicknesses. The code number refers to the weight per square metre: Code 3 is the lightest, Code 8 the heaviest in common use. The code you need depends on where the lead is being used. Using too light a code is one of the most common causes of premature failure.

Lead Code Grades - Which One Goes Where

• Code 3 - the thinnest grade in normal use. Suitable only for soakers (the small pieces that sit under tiles at a chimney or dormer side). Should not be used for visible flashings or in exposed positions.
• Code 4 - the standard grade for most step flashings, cover flashings and chimney aprons on a typical pitched roof. A minimum of Code 4 should be used for most residential flashings.
• Code 5 - used for valley gutters, back gutters behind chimney stacks, parapet gutters and flat roof upstands. The additional thickness is needed where the lead sits in a position that holds water or is exposed to constant thermal movement.
• Code 6 and above - used for larger flat areas, such as bay window flat roofs, lead-covered dormers or decorative work on heritage buildings. Code 6 is common for bay roof coverings where the whole top surface is lead-clad.

Lead work should be carried out to BS EN 12588, the standard that sets out minimum thicknesses and material quality for milled lead sheet used in construction. When you are getting quotes, asking which code the contractor intends to use tells you a great deal about the quality of what you are buying.

The Main Options for Roof Flashings

Lead is not the only material used for flashings, and it is worth understanding what the alternatives are so you can make an informed decision.

Sand-cast lead is traditional and is used on some heritage and listed buildings. It has a slightly different surface texture to milled lead and is generally thicker. It is more expensive and usually reserved for specialist or conservation work.

Milled lead sheet is the standard material for almost all residential and commercial lead work today. It is consistent in thickness, available in all codes, and is what most roofers will use as a matter of course.

Lead-effect aluminium flashings are sometimes offered as a budget alternative. These come pre-formed in lengths and are pressed into place. They are cheaper to supply and faster to fit, but they are not hand-dressed to shape and do not conform as precisely to irregular masonry. They can be adequate on a straightforward new-build chimney, but on older, uneven brickwork they are prone to gaps. They are also not suitable for valley gutters or any application where the material needs to carry water.

EPDM rubber can be used for flat roof upstands and abutments in some situations, particularly on flat roofs already covered in EPDM. It bonds chemically to itself and forms a continuous seal. It is not a substitute for lead in all situations, but for a flat roof that meets a wall, it is a legitimate system.

Pros and Cons of Lead vs. the Alternatives

• Lead - pros: extremely long lifespan when correctly installed, moulds to any shape, proven on chimneys, valleys and parapets for centuries, widely understood by surveyors and buyers.
• Lead - cons: higher material cost than alternatives, heavier (relevant on some heritage structures), can be stolen from exposed roof areas.
• Lead-effect aluminium - pros: lower cost, faster to fit, not a theft target.
• Lead-effect aluminium - cons: does not hand-dress to shape, shorter service life, not suitable for valley work or where precise conformity is needed, may not satisfy a building surveyor on an older property.
• EPDM rubber upstands - pros: seamless bond when used with an EPDM flat roof system, good for abutment work, resistant to UV degradation.
• EPDM rubber upstands - cons: not appropriate for chimney flashings or valley gutters, requires the substrate to be compatible.

Section Lengths and Fixings - Why They Matter

One detail that separates a properly specified lead job from a rough one is section length. Lead expands and contracts with temperature changes, and if a single piece runs for too long without a break, that movement causes the lead to crack over time. The industry standard is to keep individual sections to around 1.5 metres maximum, with each piece overlapping the next by at least 100mm.

The top edge of a flashing is fixed by tucking it into a raglet - a horizontal chase cut into the mortar joint of the brickwork - and then pointing over it with fresh mortar. The lead should also be fixed with clips at intervals along its length so it cannot slip. Without these clips, thermal expansion causes the lead to creep downward, eventually opening a gap at the top edge.

Ask any contractor you are considering to explain how they will fix the lead, what code they will use and how long each section will be. A straightforward, confident answer to these questions is a good sign.

Heritage and Older Properties

Older properties sometimes have original lead work that is still in reasonable condition. Lead does not need replacing simply because it is old; it needs replacing when it is cracked, crystallised, corroded or has been incorrectly laid in the first place. A roofer should be able to tell you clearly which sections need to come off and which can stay, rather than recommending a wholesale replacement when selective repairs would do the job.

If you are in Lakenheath and are unsure about the condition of your lead work, or you need to know what material to specify for a repair or replacement, call Newmarket Roofers for a roof survey. We will tell you exactly which code is appropriate, whether repair or replacement is the right call, and what the work involves.