The junction where the flat roof covering meets the lantern kerb is a weak point on many extensions. We carry out flat roof junction and flashing repairs across Greater London, with a guide price from your photos and a fixed price in writing before any work starts.

Signs you need flat roof junction and flashing repairs
- Leak near the lantern but not from the frame
- Splits, blisters or lifted edges in the roof covering by the kerb
- Ponding on the roof next to the lantern
What usually causes it?
Unbonded membrane
EPDM or single-ply that has come away from the kerb lets water run behind it.
Cracked GRP
Fibreglass roofs can crack at the kerb corner where movement concentrates.
Roof lanterns in Greater London
Drier, sunnier parts of the UK are kinder to seals than the wet west, but strong sun ages sealant, gaskets and plastic end caps, and south- or west-facing lanterns can make rooms very warm. Solar control glass and an opening vent help.
Across London, many lanterns sit on rear extensions with access only through the house, so we protect floors and plan the work to keep time indoors to a minimum. Parking and any permits are factored into the quote.
- Westminster
- Islington
- Bexley
- Barking
- Archway
- Sutton
- Croydon
- Ilford
- Enfield
- Harrow
- Tottenham
- Walthamstow
- Dagenham
- Becontree
- Romford
- Hayes
- Wembley
- Fulham
- Edmonton
- Southall
- Putney
- Battersea
- Canary Wharf
- Purley
- Peckham
- Chingford
- Uxbridge
- Wimbledon
- Stamford Hill
- Brixton
- Hounslow
- Finchley
- Cricklewood
- Mitcham
- Feltham
- Acton
- Beckenham
- Chelsea
- Streatham
- South Croydon
- Leytonstone
- Eltham
- Morden
- Carshalton
- Catford
- Willesden
- Canning Town
- Holloway
- Welling
- Shepherds Bush
- Surbiton
- Greenford
- Heston
- Stratford
- Chiswick
- Thamesmead
- Ruislip
- Greenwich
- Barnet
- Kilburn
- Wood Green
- Muswell Hill
- Bow
- Highbury
- Camden Town
- Northolt
- Coulsdon
- Hornchurch
- Blackheath
- Isleworth
- Chalk Farm
- New Malden
- Hanworth
- Woodford Green
- Richmond
- Barnes
- Notting Hill
- Wallington
- Pimlico
- Hampton
What should you expect to pay for flat roof junction and flashing repairs in Greater London?
Most flat roof junction and flashing repairs jobs come in between £245 and £695 ex VAT (£294–£834 including 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.
Flat roof junction and flashing repairs in Greater London: questions
What does a junction repair cost?
Usually £245–£695 ex VAT, confirmed in writing before work starts.
Can you repair a GRP roof without it showing?
Repairs are colour-matched as closely as possible, but new topcoat next to weathered topcoat can look slightly different at first.
Which towns in Greater London do you cover?
All of Greater London, including Westminster, Islington, Bexley, Barking, Archway, Sutton. Rural and remote addresses are covered by arrangement.
How do I get a price for flat roof junction and flashing repairs in Greater London?
Send a few photos of the lantern and the problem with your postcode, by WhatsApp or the form. We reply with a guide price and confirm the fixed price in writing before any work starts.
Other repairs in Greater London
- Roof lantern resealing in Greater London
- Upstand and kerb repairs in Greater London
- Solar control and self-cleaning glass upgrades in Greater London
- Roof lantern respraying in Greater London
- Leak investigation and inspection in Greater London
- Urgent leak make-safe in Greater London
Nearby areas
- Flat roof junction and flashing repairs in Surrey
- Flat roof junction and flashing repairs in Hertfordshire
- Flat roof junction and flashing repairs in Buckinghamshire
- Flat roof junction and flashing repairs in Essex
- Flat roof junction and flashing repairs in Berkshire
More about flat roof junction and flashing repairs · All roof lantern repairs in Greater London