Roof Lantern Leak Investigation and Inspection

Some leaks are obvious; many aren't. A leak investigation is a dedicated visit to find exactly where water gets in — lantern, kerb, roof or something else — so you only pay to fix what has actually failed.

Surveyor on a step ladder inspecting the eaves of a roof lantern with a torch and moisture meter

What are the signs you need leak investigation and inspection?

Previous repairs haven't stopped the leak
The leak moves around or is intermittent
You're not sure if it's a leak or condensation
You need a written report for a landlord, insurer or builder

What usually causes it?

Hidden water paths

Water can travel along bars, decks and linings before it shows.

More than one fault

Older lanterns often have two or three small failures.

Not the lantern

Sometimes the source is the flat roof, a parapet, a gutter or a wall above.

How do we fix it?

Inside and outside checkWe check linings, frame, glass, ridge, eaves, kerb and roof.
Water testWhere the source isn't clear, we water-test in sections, working from the bottom up.
Written findingsYou get photos, findings and a fixed price for the repair.

Why work from the bottom up when water testing?

Testing the lowest details first means water from a higher test can't confuse the result. It's slower than hosing the whole lantern, but it's how you find the real source rather than guessing.

What should you expect to pay for leak investigation and inspection?

Guide price, per visit£145–£295 ex VAT£174–£354 inc VAT · inspection, water testing where needed and a written report

Guide prices assume a standard lantern on a single-storey roof with safe ladder access. Where a tower or scaffold is needed we add it to the quote (typically £245–£895 ex VAT). Diagnostic visits start from £145 ex VAT. Your fixed price is confirmed in writing before any work starts. See all guide prices.

Questions about leak investigation and inspection

What does a leak investigation cost?

Visits start from £145 ex VAT, up to around £295 for larger lanterns or longer water tests. The cost and what's included are confirmed in writing before we visit.

Is the visit cost deducted from the repair?

Ask when you book — we'll confirm in writing how the visit is charged if you go ahead with the repair.

Do you provide a report?

Yes, with photos and findings, which is useful for landlords, insurers and disputes with installers.

Where do we carry out leak investigation and inspection?

We cover the whole of the UK. Choose your area for local details and towns we cover.

England

Wales

Scotland

Northern Ireland

Get a guide price

Tell us what's happening. We reply with a guide price and the next step — the fixed price is always confirmed in writing before any work starts.

Roof lantern leak investigation and inspection