Lead Work in Soham

Expert Lead Work
in Soham

What Lead Work Is and Why It Matters

Lead is used at every junction on a roof where a tile or slate cannot make a watertight seal on its own. That means chimney stacks, dormer walls, abutments where a roof runs into a higher wall, lead valleys between two roof slopes, and the soakers tucked under individual slates alongside a chimney. Done properly, using the correct lead code and working to BS EN 12588, lead flashing can outlast the tiles beneath it. Done poorly, it becomes the most likely source of a slow, damaging leak.

The skill in lead work is not just in cutting and dressing the sheet metal. It's in understanding thermal movement - lead expands and contracts significantly with temperature changes - and installing each piece so that movement doesn't crack the joint or pull the fixing. Every piece in a step flashing run should be no longer than 1.5 metres, lapped at the joints, and fixed at the top only so that it can move freely at the bottom.

What a Good Installation Looks Like

After new lead work is completed on your Soham property, you should see neat, dressed sheet lead sitting close against the masonry or tiles with no visible gaps. The top edge should be tucked into a raked-out mortar joint (a raggle) and re-pointed with fresh mortar, not sealed with silicone. The lead itself should lie flat and smooth, without ripples or kinks that suggest it was forced rather than dressed. Step flashings should overlap cleanly at the joints, with each piece sitting over the one below.

If there is a lead valley, the sheets should overlap by at least 150 mm and the valley boards beneath should be sound. If the installer lifted any tiles or slates to fit soakers, those tiles should be re-laid properly with no missing or cracked pieces left in place.

Aftercare in the First Few Months

New lead needs a short settling period. In the first season after installation, the lead will oxidise on the surface and develop a dull grey patina. This is normal and expected - it is actually a protective layer of lead carbonate and lead sulphate that resists further corrosion. You do not need to paint it, seal it or treat it in any way.

What you should do in the first few months is keep an eye on the interior of your home near the repaired junction. If the previous leak has caused damp to build up in plaster or timber, it may take time to dry out even after the source has been fixed. A patch that seems to persist does not necessarily mean the lead work has failed - check whether there is adequate ventilation in the roof space and whether the damp is reducing over time. If a stain spreads rather than fades, that is worth investigating.

Simple Maintenance That Avoids the Next Problem

Lead flashings don't require regular maintenance in the same way that, say, gutters do. But there are a handful of checks that, done once a year, will catch problems early and stop a minor issue becoming a significant repair.

• Check the pointing. The mortar in the raggle joint that holds the top edge of the flashing is often the first thing to fail. From the ground using binoculars, look for gaps between the lead and the masonry at chimney level. Cracked or missing mortar lets water in behind the flashing and can cause the lead to lift.
• Look for lifting or bowing. A piece of lead that has lifted away from the wall, even slightly, is no longer waterproof at that edge. Wind can get underneath it and make the problem worse quickly.
• Clear debris from valleys. A lead valley that fills with leaves and wet debris holds moisture against the lead surface for long periods. It also restricts water flow and can cause water to back up under the tiles. Clearing a valley takes minutes and extends its life considerably.
• Watch for moss on adjacent tiles. Moss near a lead flashing holds moisture and gradually causes the mortar in nearby pointing to break down. Dealing with moss on the tiles around a chimney or dormer protects the lead as much as it protects the tiles.
• Check after storms. High winds can lift the unsupported lower edge of a flashing, particularly if the fixing at the top has already begun to fail. After any severe weather, a quick visual check from the ground with binoculars is worthwhile.

What Not to Do Yourself

Filling gaps at a chimney junction with silicone or mastic is a common DIY fix that causes more problems than it solves. Silicone does not bond well to lead or masonry over time, and it prevents you (or a roofer) from properly assessing the condition of the lead underneath. When a roofer eventually removes a silicone patch, they often find extensive deterioration that could have been caught and repaired more cheaply years earlier.

Similarly, pressing lead back down by hand or trying to re-point mortar at height without the correct access is both dangerous and usually ineffective. The mortar mix for raggle joints is specific - a 1:3 cement to sharp sand mix is typical - and improperly mixed pointing will crack out again within a season or two.

When to Call a Roofer Rather Than Wait

If you spot any of the following, it's worth calling for a proper inspection rather than monitoring and hoping:

• A fresh damp patch on an interior ceiling near a chimney, dormer or roof window.
• Visible gaps between the lead and the masonry that weren't there before.
• Lead that has clearly cracked, split or corroded through.
• Pointing that has fallen out of a raggle joint, leaving the top edge of the flashing unsupported.

Lead leaks tend to worsen over autumn and winter when rainfall is heavier and temperatures drop. A small repair carried out in early autumn is almost always cheaper than the same job plus associated interior damage carried out the following spring.

How Long Well-Maintained Lead Lasts

Lead flashings installed to the correct specification with the appropriate code for each application can last forty to sixty years before replacement is needed. The installations that fall short of this - sometimes failing within ten to fifteen years - are almost always those where the wrong code was used, the pieces were cut too long and couldn't move freely, or the fixing into the raggle was inadequate. Good aftercare extends the life of even a modest installation.

Get in Touch About Your Soham Property

If you've had lead work done recently and want a maintenance check, or if you've spotted early signs of trouble on your chimney or dormer, call Brandon Roofers. We cover Soham and the surrounding area and can carry out a thorough inspection so you know exactly where things stand.