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 Cornwall, 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
- Missing or loose edge trims and flashings
- 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 Cornwall
Damp, mild winters keep moss and algae growing on flat roofs and lantern frames, which holds water against seals and blocks weep slots. Regular clearing makes a real difference in wetter areas.
Near the coast, salt in the air is hard on aluminium finishes and fixings; washing the frame occasionally and touching in chips keeps corrosion away.
What should you expect to pay for flat roof junction and flashing repairs in Cornwall?
Guide price for flat roof junction and flashing repairs: £245–£695 ex VAT (£294–£834 inc 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?
Most lantern repairs in England need no approval at all. Where a job turns into a replacement, the Building Regulations 2010 apply and we confirm how the work will be signed off before we start. 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 Cornwall: questions
Do you repair the whole flat roof?
We repair the area around the lantern. If the wider roof is failing we'll tell you and can quote, but we won't push a new roof if a local repair will do.
What does a junction repair cost?
Usually £245–£695 ex VAT, confirmed in writing before work starts.
Which towns in Cornwall do you cover?
All of Cornwall, including Truro, Redruth, Falmouth, St Austell, Camborne, Newquay. Rural and remote addresses are covered by arrangement.
How do I get a price for flat roof junction and flashing repairs in Cornwall?
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 Cornwall
- Glazing bar and capping repairs in Cornwall
- Ridge and hip repairs in Cornwall
- Slipped glass panel repairs in Cornwall
- uPVC roof lantern repairs in Cornwall
- Roof lantern respraying in Cornwall
- Urgent leak make-safe in Cornwall
Nearby areas
- Flat roof junction and flashing repairs in Devon
- Flat roof junction and flashing repairs in Somerset
- Flat roof junction and flashing repairs in Bristol
- Flat roof junction and flashing repairs in Dorset
- Flat roof junction and flashing repairs in Wiltshire
More about flat roof junction and flashing repairs · All roof lantern repairs in Cornwall