We carry out flat roof junction and flashing repairs in Farnworth and across the BL4 area. The junction where the flat roof covering meets the lantern kerb is a weak point on many extensions.

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
What usually causes it?
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 Farnworth and the BL4 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.
In built-up areas, access is often the hardest part of the job — through the house, over a neighbour's roof, or with parking restrictions. We plan access in advance and price any tower or scaffold into the quote.
From Manchester to Farnworth is roughly 8 miles — all part of the Greater Manchester area we cover.
Neighbouring places we cover include Walkden (2 miles), Bolton (3 miles), Radcliffe (3 miles).
How much should it cost?
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?
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 Farnworth: questions
Do you cover Farnworth?
Yes. We cover Farnworth, including the BL4 postcode area, as part of Greater Manchester. 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.
Which places near Farnworth do you cover?
As well as Farnworth, we cover nearby Walkden, Bolton, Radcliffe, Tyldesley and the rest of Greater Manchester.
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 Farnworth
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Flat roof junction and flashing repairs near Farnworth
More about flat roof junction and flashing repairs · All roof lantern repairs in Farnworth