In Berkhamsted, 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
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.
Roof lanterns in Berkhamsted
Most inland lantern leaks aren't storm damage; they're usually tired sealant, a lifted capping or blocked eaves drainage. All three are quick to find and fix once you know where to look.
Berkhamsted is around 10 miles from St Albans, and both are within our Hertfordshire coverage.
Close by, we also cover Chesham (4 miles), Hemel Hempstead (5 miles), Amersham (7 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?
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 Berkhamsted: questions
Do you cover Berkhamsted?
Yes. We cover Berkhamsted, including the HP4 postcode area, as part of Hertfordshire. 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 Berkhamsted?
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.
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 Berkhamsted
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Flat roof junction and flashing repairs near Berkhamsted
More about flat roof junction and flashing repairs · All roof lantern repairs in Berkhamsted