In Archway, 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.

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
Unbonded membrane
EPDM or single-ply that has come away from the kerb lets water run behind it.
Missing trims
Without a trim or flashing to protect the top edge, water gets in behind the membrane.
Covering Archway 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.
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 Archway is roughly 5 miles — all part of the Greater London area we cover.
We also cover nearby Holloway (1 mile), Muswell Hill (2 miles), Chalk Farm (2 miles).
Guide prices for flat roof junction and flashing repairs in Archway
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?
Straightforward repairs — resealing, gaskets, cappings, eaves and like-for-like parts — don't normally need building regulations approval in England. Replacing the whole lantern or enlarging the opening is different and falls under the Building Regulations 2010; we confirm in writing which route applies before any replacement. 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 Archway: questions
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.
Which places near Archway do you cover?
As well as Archway, we cover nearby Holloway, Muswell Hill, Chalk Farm, Camden Town and the rest of Greater London.
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 Archway
- Glazing bar and capping repairs in Archway
- Ridge and hip repairs in Archway
- Misted glass unit replacement in Archway
- Solar control and self-cleaning glass upgrades in Archway
- Condensation diagnosis and fixes in Archway
- Commercial roof lantern repairs in Archway
Flat roof junction and flashing repairs near Archway
More about flat roof junction and flashing repairs · All roof lantern repairs in Archway