The junction where the flat roof covering meets the lantern kerb is a weak point on many extensions. Send photos from Winchester (SO23) and we'll tell you which it is — with the price agreed in writing before any work.

What you might be seeing
- 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
Common causes we find
Cracked GRP
Fibreglass roofs can crack at the kerb corner where movement concentrates.
Missing trims
Without a trim or flashing to protect the top edge, water gets in behind the membrane.
Covering Winchester and nearby
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.
From Southampton to Winchester is roughly 12 miles — all part of the Hampshire area we cover.
We also cover nearby Eastleigh (7 miles), Southampton (12 miles), Totton (13 miles).
How much should it cost?
Typical range: £245–£695 ex VAT, which is £294–£834 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.
Flat roof junction and flashing repairs in Winchester: questions
Do you cover Winchester?
Yes. We cover Winchester, including the SO23 postcode area, as part of Hampshire. Send photos by WhatsApp or the form for a free guide price, and we'll confirm the fixed price in writing before any work starts.
Do you need to visit to price flat roof junction and flashing repairs?
Not always. Clear photos are often enough for a guide price. Where the cause isn't obvious, a visit to inspect and water-test is charged from £145 ex VAT, confirmed before we come.
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.
Other lantern repairs in Winchester
- Eaves beam and gutter repairs in Winchester
- Upstand and kerb repairs in Winchester
- Misted glass unit replacement in Winchester
- Cracked lantern glass replacement in Winchester
- Solar control and self-cleaning glass upgrades in Winchester
- Urgent leak make-safe in Winchester
Flat roof junction and flashing repairs near Winchester
More about flat roof junction and flashing repairs · All roof lantern repairs in Winchester