We carry out flat roof junction and flashing repairs in Caernarfon and across the LL55 area. The junction where the flat roof covering meets the lantern kerb is a weak point on many extensions.

What you might be seeing
- 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
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.
About Caernarfon and the LL55 area
Western and upland parts of the UK get more rain and more wind-driven rain than the east, and that's what finds weak cappings and blocked eaves first. Lanterns here benefit from a check of the bars on the most exposed face and a clear eaves channel before winter.
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.
From Bangor, Gwynedd to Caernarfon is roughly 8 miles — all part of the Gwynedd area we cover.
We also cover nearby Llangefni (8 miles), Bangor, Gwynedd (8 miles), Porthmadog (16 miles).
What should you expect to pay in Caernarfon?
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 Wales?
Straightforward repairs — resealing, gaskets, cappings, eaves and like-for-like parts — don't normally need building regulations approval in Wales. Replacing the whole lantern or enlarging the opening is different and falls under the Building Regulations 2010 (as applied in Wales); we confirm in writing which route applies before any replacement. Listed buildings in Wales need listed building consent from the local planning authority for alterations, with Cadw guidance on historic buildings; check with the council before changing a lantern on a listed property.
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 Caernarfon: questions
Do you cover Caernarfon?
Yes. We cover Caernarfon, including the LL55 postcode area, as part of Gwynedd. 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.
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 Caernarfon
- Roof lantern resealing in Caernarfon
- Eaves beam and gutter repairs in Caernarfon
- Timber roof lantern repairs in Caernarfon
- Opening vent and actuator repairs in Caernarfon
- Roof lantern respraying in Caernarfon
- Urgent leak make-safe in Caernarfon
Flat roof junction and flashing repairs near Caernarfon
More about flat roof junction and flashing repairs · All roof lantern repairs in Caernarfon