A roof lantern leak is almost always a failed seal, a lifted capping, blocked eaves drainage or a problem where the kerb meets the flat roof — not a failed lantern. Send photos from Carshalton (SM5) and we'll tell you which it is — with the price agreed in writing before any work.

Signs you need roof lantern leak repairs
- Drips from a glazing bar or the eaves beam when it rains
- Water running down the inside face of the glass
- A leak that only appears in wind-driven rain from one direction
Common causes we find
Failed silicone or glazing tape
UV and thermal movement break down the seal between capping, gasket and glass. Once a gap opens, water tracks along the bar and drops at the lowest point.
Lifted or misaligned cappings
Top cappings clip or screw over each glazing bar. If one has lifted, been knocked or was never seated, rain gets straight under it.
Roof lanterns in Carshalton
Sun and UV do more damage than rain on many lanterns here: brittle ridge caps, chalky finishes and hardened gaskets. They're cheap to replace before they let water in.
London's extensions are often tight to neighbouring walls and roofs. Where a repair needs access over a neighbour's property, we'll tell you in advance so you can arrange it.
Carshalton is around 9 miles from Westminster, and both are within our Greater London coverage.
Neighbouring places we cover include Wallington (1 mile), Sutton (2 miles), Mitcham (2 miles).
Guide prices for roof lantern leak repairs in Carshalton
Typical range: £195–£595 ex VAT, which is £234–£714 with VAT, per lantern. Towers or scaffold, where needed, are priced into the quote. Your fixed price is confirmed in writing before any work starts.
Do you need permission in England?
In England, like-for-like repairs to a roof lantern don't usually involve building control. A full replacement or a bigger opening is controlled under the Building Regulations 2010, so we set out the route in writing first. Listed buildings need listed building consent from the local council for alterations, and conservation areas can have extra controls; like-for-like repairs are treated differently from changes, so check with the council's conservation officer first.
How does it work?
- Send photosWhatsApp or upload a few photos and tell us when it leaks.
- Guide priceWe reply with a guide price and whether a visit is needed.
- Fixed price in writingYou approve the price and the date before anything starts.
- Repair and testWe fix what's failed, water-test where it matters, and send photos.
Roof lantern leak repairs in Carshalton: questions
How do I get a price for roof lantern leak repairs in Carshalton?
Send a few photos of the lantern and the problem, with your Carshalton postcode. We'll reply with a guide price and tell you whether a visit is needed before we can fix the price.
Which places near Carshalton do you cover?
As well as Carshalton, we cover nearby Wallington, Sutton, Mitcham, Morden and the rest of Greater London.
How much does a roof lantern leak repair cost?
Most leak repairs fall between £195 and £595 ex VAT for a standard lantern with ladder access. The fixed price is confirmed in writing before any work starts.
Can you fix the leak in the rain?
We can make the lantern safe in wet weather, but sealants and tapes need a dry, clean surface to bond, so permanent repairs are done in a dry window.
Other lantern repairs in Carshalton
- Ridge and hip repairs in Carshalton
- Eaves beam and gutter repairs in Carshalton
- Misted glass unit replacement in Carshalton
- Slipped glass panel repairs in Carshalton
- uPVC roof lantern repairs in Carshalton
- Opening vent and actuator repairs in Carshalton
Roof lantern leak repairs near Carshalton
More about roof lantern leak repairs · All roof lantern repairs in Carshalton