Leaks & repairs

Why is water coming in around my chimney?

Short answer: Common causes include failed lead flashings, open mortar joints, cracked flaunching, porous masonry and defects in nearby tiles or underlay. The chimney itself is not always the entry point.

What this means in practice

Water can travel along underlay, rafters and battens before it appears indoors, so the stain is a clue rather than proof of the entry point. A sound diagnosis combines the weather pattern, an internal loft inspection and a close external check of the covering and every nearby junction.

What to check next

  • Inspect lead, masonry and coverings together
  • Check which chimney face is exposed to the weather
  • Avoid sealing moisture into defective masonry

When should you ask a roofer to inspect it?

Book an inspection when a leak is active or recurring, the source is unclear, timber or insulation is staying wet, or a previous patch has failed. Water near electrics, a sagging ceiling or loose material above a public area needs urgent attention.

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

Would you like a property-specific answer?

Request an inspection and written quotation from J&L Welch.

No deposit is required. Payment is due on completion within seven days, with the agreed scope and price confirmed in writing.

Request a quotation