Chimneys, leadwork & roofline

Why does lead flashing crack or split?

Short answer: Lead expands and contracts. Oversized pieces, poor support, incorrect detailing, fatigue or unsuitable fixings can concentrate movement and cause failure.

What this means in practice

Chimneys, valleys, abutments, ridges, verges and eaves are where different materials and movements meet. Repairs must address the supporting masonry or timber as well as the visible lead, mortar, plastic or metal finish.

What to check next

  • Use appropriate lead codes and bay lengths
  • Fix without preventing natural movement
  • Check the masonry chase and surrounding coverings

When should you ask a roofer to inspect it?

Arrange close inspection for loose masonry, repeated staining around a chimney, split lead, detached verge units or gutters that still overflow after cleaning. Scaffold-dependent repairs should be grouped where sensible so access is not paid for twice.

Safety first: do not climb onto a roof without suitable access, training and protection. Keep clear of loose coverings, unstable ceilings and water near electrical fittings.

Technical content reviewJ & L Welch Roofing & Paving Services Ltd · Over 20 years of combined roofing experienceReviewed 28 August 2026 · How our answers are produced

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