Lead Work in Histon

Expert Lead Work
in Histon

What lead work actually involves

Lead is used wherever a roof meets a vertical surface: around chimneys, along the sides of dormers, at the junction between a flat roof and a house wall, and in the valleys between two roof slopes. When it is fitted and dressed correctly, it forms a watertight seal that outlasts most other roofing materials. When it fails, water finds its way in quickly and the damage often spreads well before you notice a stain on a ceiling.

That means using the correct code of lead for each location, cutting and dressing it to the profile of the roof by hand, and lapping and fixing it properly so it can expand and contract with temperature changes without cracking or lifting.

Why lead fails in the first place

Lead that is fitted in a single unbroken sheet across a long run will crack over time. Lead expands significantly in warm weather and contracts in cold, and if it cannot move freely it will split. The correct method is to work in lengths no greater than about 1.5 metres, with each length overlapping the next and fixed in a way that allows movement.

A common problem is flashing that has been pointed into a mortar joint and then forgotten. The mortar shrinks and cracks, the lead lifts at the edge, and rain runs behind it. Another common failure is patched or overworked lead that has been hammered and re-dressed so many times it has work-hardened and become brittle. At that point, patching again is not a solution.

How to choose a lead work contractor in Histon

Lead work is a skilled trade. It looks straightforward from a distance, but dressing lead correctly around a chimney stack or into a valley takes experience and the right tools. Choosing the wrong contractor can leave you with a roof that leaks within a season, and sorting out poorly done lead work costs more than having it done properly the first time.

Here is what to ask before you agree to any lead work:

• What code of lead will you use? Lead comes in different thicknesses, referred to as codes. Code 3 is the lightest and is only appropriate for certain soakers. Flashings around chimneys and dormers should be code 4 or 5. Valley linings are typically code 5 or 6. A contractor who cannot answer this question, or who gives vague answers, is worth treating with caution.
• Will the lead be hand-dressed on site? Some contractors use pre-formed lead products as a shortcut. These have their place in certain situations, but bespoke hand-dressing is the correct approach for most traditional roofing applications, because it can be shaped precisely to the profile of your roof.
• How will the flashing be fixed to the wall? The correct method is to chase the lead into a mortar joint at the top, fold and dress it against the wall face, and then repoint. Ask whether they will rake out the old mortar properly before repointing, and what mortar mix they use. Too strong a mix and the joint will crack again quickly.
• What is the maximum length per section? As noted above, sections longer than about 1.5 metres are liable to crack. If a contractor says length does not matter, that is a red flag.
• Will they remove all the old lead, or patch over it? Patching a badly failed or work-hardened flashing is a short-term fix. Ask whether they are stripping the old material entirely and starting fresh, or patching existing lead. There are cases where patching is fine, but you should know which approach is being taken and why.
• Can they show you what they plan to do before they start? A straightforward job should be easy to explain. Ask the contractor to walk you through the work: what they will strip out, what they will replace, how they will fix and point it. If the explanation is vague, that is worth noting.

What a good quote should cover

Before agreeing to any lead work, make sure you have a written quote that sets out the scope clearly. It should state which areas of the roof are being worked on, the code and approximate quantity of lead being used, and what preparation work is included (stripping old lead, raking out mortar joints, replacing damaged timber if needed). A quote that just says "supply and fix flashing" tells you very little.

Be wary of quotes that seem very low. Lead itself is not cheap, and the time needed to dress it properly is significant. A contractor cutting corners on material or time will produce work that fails earlier than it should.

Typical costs for lead work

Lead flashing repair to a chimney will vary depending on how much lead needs replacing and whether re-pointing is also required. A full chimney stack re-lead with back gutter, step flashings and front apron runs considerably more. Valley replacements vary considerably with the length of the valley and the pitch of the roof. Costs depend on access, roof height and the condition of the existing structure.

Scaffolding and access

Ask whether scaffolding is included or whether the contractor plans to work off a ladder. For chimney stacks above two-storey height, or for any valley or parapet work, scaffold or a tower is the safer and more practical option. Working off a ladder makes it very difficult to dress lead properly because you cannot get the right angle and pressure. If a quote is significantly lower than others, it may be because scaffolding has been left out.

What to do if you suspect a lead failure now

If you have a leak at a chimney, dormer or flat roof junction, try to catch the water with a container and make a note of exactly where it appears on the ceiling relative to the roof above. That information helps a roofer locate the source faster. Do not attempt to seal failing lead yourself with mastic or sealant strips; these products do not bond reliably to lead, and they hide the problem rather than fixing it, which makes the eventual repair harder.

Call us to arrange a roof survey in Histon and we will inspect the lead work, tell you exactly what needs doing, and give you a clear written quote before any work starts.