Lead Work in Sawston

Expert Lead Work
in Sawston

What lead work covers

Lead is the material of choice for sealing the junctions between your roof and any vertical surface: chimney stacks, dormer cheeks, bay window roofs, flat roof abutments and the valleys between two pitches. A correctly fitted lead flashing, dressed by hand to BS EN 12588 standard, will outlast almost any other waterproofing material in these positions. When lead fails, leaks follow quickly, because these are exactly the points where rain is most likely to be driven in.

All our lead work is hand-dressed on site. We cut and dress each section to suit the profile of your specific roof rather than relying on pre-formed pieces that may not fit tightly enough to do the job properly.

Why lead work fails

Lead expands and contracts with temperature. If it is fitted in sections that are too long, or fixed rigidly so it cannot move, it will split. Sections should be no longer than about 1.5 metres for this reason. A common problem is also flashing that has been chased into a mortar joint and then repointed with too hard a mortar mix; as the lead moves seasonally, the mortar cracks and the flashing lifts.

Old lead that has been patched repeatedly can also become work-hardened and brittle. Every time lead is dressed and re-dressed, it loses some of its natural softness and flexibility. Eventually it will crack no matter how carefully it is handled, and at that point the only lasting answer is replacement.

Repair or replace: how to decide

This is the question most homeowners in Sawston face when a roofer tells them the lead work needs attention. The honest answer depends on the condition of the existing lead, how long it has been in place, and what caused the problem in the first place.

When a repair is the right answer

A repair is appropriate when the lead itself is still in good, flexible condition and the failure is isolated. The most typical cases are:

• A mortar joint that has cracked and allowed a section of flashing to lift. The lead can be re-dressed and the joint can be properly raked out and repointed without replacing the lead itself.
• A small split or pinhole in lead that is otherwise sound and flexible. A properly executed patch using the correct code of lead, bonded with lead solder rather than sealant, can be a long-term fix if the surrounding material is in good condition.
• A poorly fitted soaker that has slipped or was never correctly set under a tile. This is a straightforward job that does not require the surrounding flashings to be disturbed.
• A front apron flashing that has pulled away from the wall but has not cracked or hardened. Re-dressing and repointing may be all that is needed.

The key question to ask a roofer before agreeing to a repair is: is the rest of the lead in this area flexible and in good condition? If the answer is yes, a targeted repair makes sense. If the answer is uncertain, ask them to show you what they mean, or to flex a corner of the lead gently to demonstrate.

When replacement is the better choice

Replacement is the right call in more situations than homeowners sometimes expect. The most common ones are:

• Old, work-hardened lead. Lead that has been on a roof for many decades, particularly on pre-1970s properties, may have been dressed and re-dressed multiple times. If it is brittle or crumbling at the edges, no repair will hold reliably. Replacement is more economical in the long run because a repair will fail again within a few years.
• Repeated failures in the same area. If the same flashing has been repaired two or three times without lasting success, the underlying problem may be structural: a chimney stack that has moved, a parapet wall that has lost its coping, or a roof pitch that has settled. Replacing the lead gives you the opportunity to address the root cause rather than patch over it again.
• Lead that was the wrong code to begin with. If the original contractor used code 3 lead where code 5 was required, no amount of patching will compensate for the fact that the material is too thin for the application. Full replacement with the correct specification is the only lasting fix.
• Extensive cracking across a valley or parapet. When cracking is widespread rather than isolated, a patch will only shift the point of failure without solving it. Replacing the whole run at once is more cost-effective than repeated call-outs.

The cost difference between repair and replacement

A repair to an isolated section of chimney flashing in and around Sawston typically costs in the range of £150 to £400, depending on access and the extent of work involved. A full re-lead of a chimney stack, including back gutter, step flashings and front apron, is more typically in the range of £600 to £1,200. Valley lining replacement varies considerably with the length of the valley and the code of lead specified, but a typical domestic valley is often in the range of £400 to £900.

The temptation to choose the cheaper repair is understandable, but if the lead is already near the end of its useful life, a repair may only delay the inevitable by a few years while costing you call-out fees in the meantime. A roofer worth trusting will tell you honestly when they think replacement offers better value, not just quote you for the job that earns them the most.

Questions to ask before you decide

• Is the lead in this area still flexible, or is it hard and cracking?
• Is this the first failure here, or has it been repaired before?
• Is the lead the correct code for this application?
• If you patch it now, how long is that patch likely to last given the condition of the surrounding material?
• Is there any underlying structural movement that is causing the failure?

A roofer who gives straight answers to these questions is one you can work with. If you get vague reassurances without explanation, ask again or get a second opinion.

Getting the work done properly

Whether you go ahead with a repair or a full replacement, make sure the lead used is the correct BS EN 12588 code for the position, that sections are kept to about 1.5 metres maximum length, and that any mortar repointing is done with a mix appropriate for the age and type of brick. On older properties this means a lime-based mortar rather than a strong cement mix, which can damage softer brick.

Contact Newmarket Roofers to arrange an inspection of your lead work in Sawston. We will tell you honestly what condition it is in and whether repair or replacement makes more sense for your roof.