Lead Work in Linton

Expert Lead Work
in Linton

Why Lead Work Fails - and What to Look For

Lead is one of the most durable materials used on a roof, but it is not indestructible. When it fails, it tends to do so slowly and quietly - meaning water can be getting in for months before you notice anything inside the house. Knowing the warning signs early can save you from a much bigger repair bill.

The most telling sign is a damp patch or brown tide mark on a ceiling or upper wall, particularly near a chimney breast, a dormer, a bay window roof, or where an extension meets the main house. These are all points where lead flashing is used to seal the join between the roof and a vertical surface. When that seal breaks, rainwater tracks down the gap and into the building.

Warning Signs You Should Not Ignore

There are several things worth checking from ground level or from inside the loft. You do not need to go on the roof yourself - in fact, please do not unless you are trained to do so safely.

• Staining on chimney breasts inside - a yellow or brown watermark on the plaster near the chimney is a strong indicator that step flashing or soakers have failed.
• Damp smell in a loft or top-floor room - particularly after rain. This can point to a slow weep rather than an obvious drip.
• Visible cracks or splits in the lead - if you can see the lead on a flat roof abutment or valley from a window or from ground level, look for crazing, splits or areas where the lead has curled away from the wall.
• Mortar missing from the raglet - the raglet is the groove cut into the masonry where the top edge of the flashing is tucked. If the mortar pointing has cracked out, water gets straight behind the flashing.
• Lead that has slipped downward - this is a sure sign it was never fixed correctly. Properly fitted step flashing is dressed into the mortar joints and held firm; if pieces have dropped, the fixing has failed.
• White efflorescence on brickwork - salt deposits on the outside of a chimney stack or parapet wall often appear where water has been soaking through repeatedly.
• Blistered or bubbled paint on a ceiling - even without a visible stain, paint lifting near a chimney or external wall junction is worth investigating.

What Actually Causes Lead Work to Fail

Lead moves. It expands in warm weather and contracts in the cold, and over time that repeated thermal movement causes the metal to fatigue. This is why lead flashings are always laid in short sections - typically no more than 1.5 metres - with overlap joints between each piece. When that rule is ignored and a single long run is laid, cracking along the length is almost inevitable.

Poorly dressed lead is another common cause. Lead has to be pressed tightly against the surface it is sealing, whether that is brick, stone, render or timber fascia. If a roofer has simply bent it roughly into shape without proper hand-dressing tools, gaps form and water finds its way in. Lead work should be hand-dressed on site and the sheet used should meet the minimum thickness requirements set out in BS EN 12588.

Old lead does not always need replacing outright. Lead that was correctly installed can last for many decades, but it may need its mortar pointing renewed or a section re-dressed where movement has pulled it away. The decision to repair or replace depends on the condition of the lead itself - if it is heavily corroded, crystallised or cracked through, replacement is the right call.

Chimney Flashings - the Most Frequent Problem Area

Chimneys are the single most common location for lead failure on a pitched roof. A chimney stack needs flashing on all four sides: front apron flashing at the lower edge, back gutter or back flashing at the upper edge, and step-and-soaker flashings up each side. If any one of these fails, water gets in. Many older properties have had only a portion replaced over the years, leaving mismatched lead of different thicknesses and ages that wears unevenly.

On some properties, the original lead was replaced at some point with mortar fillet instead - a wedge of sand and cement butted up against the chimney base. Mortar fillet always cracks eventually, and it is not a satisfactory long-term substitute for proper lead flashing. If your chimney flashing is a mortar wedge, it is worth having proper lead fitted when the time comes to repair it.

Valley Gutters and Flat Roof Abutments

Valley gutters - the internal angles where two roof slopes meet - are another area where lead is widely used. A lead valley collects and channels water from both slopes into the gutter below. If the lead is too thin (typically anything below Code 4 for this application), if it has been laid without adequate falls, or if debris has built up and held water against the surface, corrosion accelerates and leaks follow.

Flat roof abutments - where a flat or low-pitch roof meets a wall - also rely on upstand flashings to direct water away from the wall junction. These upstands need to be turned up high enough and properly secured. A common fault is an upstand that is too short, allowing wind-driven rain to get behind it.

When to Call a Roofer

Any internal damp near a roof junction warrants a closer look before the next patch of wet weather arrives. Lead leaks rarely heal themselves, and water ingress that continues through winter can damage timbers, insulation and plasterwork well beyond what the original repair would have cost.

If you are a homeowner in Linton and you have noticed any of the signs described here, call us for a roof survey so we can identify exactly where the lead is failing and give you a clear picture of what the repair involves. Newmarket Roofers carry out step flashing repairs, full chimney flashing replacements, valley re-leads and parapet flashings across the area - all hand-dressed on site to the correct standard.