Resealing is the planned, whole-lantern version of a leak repair: we cut out the old, failed sealant, clean every joint back to a sound surface and reseal the cappings, ridge and eaves with materials that suit the frame. Send photos from Dagenham (RM10) and we'll tell you which it is — with the price agreed in writing before any work.

What you might be seeing
- Black mould or dirt lines trapped in old silicone
- Several small leaks rather than one obvious one
- A lantern that is 8–15 years old and has never been maintained
Why it happens
Sealant past its life
Exposed sealant on a roof takes UV, frost and constant expansion and contraction. It hardens, loses grip and pulls away from the glass.
Patch over patch
Fresh sealant run over old, dirty sealant rarely bonds. It looks fixed for a season and then lets go.
Roof lanterns in Dagenham
Even in drier areas, one heavy downpour with blocked eaves is enough to overflow a lantern indoors. Clearing the eaves channel is the simplest prevention there is.
London's extensions are often tight to neighbouring walls and roofs. Where a repair needs access over a neighbour's property, we'll tell you in advance so you can arrange it.
We cover Dagenham as part of Greater London, about 13 miles from Westminster.
If you're just outside Dagenham, we also cover Becontree (2 miles), Romford (2 miles), Hornchurch (2 miles).
How much should it cost?
Typical range: £245–£495 ex VAT, which is £294–£594 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?
Most lantern repairs in England need no approval at all. Where a job turns into a replacement, the Building Regulations 2010 apply and we confirm how the work will be signed off before we start. 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.
Roof lantern resealing in Dagenham: questions
Do you need to visit to price roof lantern resealing?
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.
Can you repair a lantern someone else installed in Dagenham?
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.
How much does it cost to reseal a roof lantern?
A standard-size lantern on a single-storey extension is usually £245–£495 ex VAT. Larger lanterns, difficult access or gasket replacement add to that, and you get the fixed price in writing first.
How long does resealing take?
Most domestic lanterns take a few hours in dry weather.
Other lantern repairs in Dagenham
- Cracked lantern glass replacement in Dagenham
- Slipped glass panel repairs in Dagenham
- Opening vent and actuator repairs in Dagenham
- Flat rooflight and skylight repairs in Dagenham
- Urgent leak make-safe in Dagenham
- Roof lantern replacement in Dagenham
Roof lantern resealing near Dagenham
More about roof lantern resealing · All roof lantern repairs in Dagenham