In Boston, 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
- 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
Why it happens
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.
About Boston and the PE21 area
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.
Coastal wind drives rain hard against lanterns, so cappings and ridge seals on the seaward face take the most punishment.
From Lincoln to Boston is roughly 27 miles — all part of the Lincolnshire area we cover.
Close by, we also cover Spalding (14 miles), Skegness (19 miles), Wisbech (23 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?
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 Boston: questions
Do you cover Boston?
Yes. We cover Boston, including the PE21 postcode area, as part of Lincolnshire. 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.
How do I get a price for flat roof junction and flashing repairs in Boston?
Send a few photos of the lantern and the problem, with your Boston postcode. We'll reply with a guide price and tell you whether a visit is needed before we can fix the price.
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 Boston
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- Timber roof lantern repairs in Boston
- Aluminium roof lantern repairs in Boston
- uPVC roof lantern repairs in Boston
- Orangery lantern repairs in Boston
- Commercial roof lantern repairs in Boston
Flat roof junction and flashing repairs near Boston
More about flat roof junction and flashing repairs · All roof lantern repairs in Boston