In Harrow, as everywhere, the junction where the flat roof covering meets the lantern kerb is a weak point on many extensions. Send photos and we'll tell you what we think has failed.

Signs you need flat roof junction and flashing repairs
- Splits, blisters or lifted edges in the roof covering by the kerb
- Missing or loose edge trims and flashings
- 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.
About Harrow and the HA2 area
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.
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.
From Westminster to Harrow is roughly 10 miles — all part of the Greater London area we cover.
If you're just outside Harrow, we also cover Wembley (2 miles), Northolt (3 miles), Greenford (4 miles).
How much should it cost?
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?
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 Harrow: questions
Do you cover Harrow?
Yes. We cover Harrow, including the HA2 postcode area, as part of Greater London. 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.
Can you repair a lantern someone else installed in Harrow?
Yes. We repair lanterns whoever fitted them. If yours is still under the installer's warranty, contact them first so you don't affect it.
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.
Other lantern repairs in Harrow
- Slipped glass panel repairs in Harrow
- Timber roof lantern repairs in Harrow
- Roof lantern respraying in Harrow
- Flat rooflight and skylight repairs in Harrow
- Cleaning and maintenance in Harrow
- Commercial roof lantern repairs in Harrow
Flat roof junction and flashing repairs near Harrow
More about flat roof junction and flashing repairs · All roof lantern repairs in Harrow