We carry out roof lantern resealing in Blackheath and across the SE3 area. 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.

What you might be seeing
- Cracked, split or shrunken sealant along the bars
- Black mould or dirt lines trapped in old silicone
- Several small leaks rather than one obvious one
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.
Covering Blackheath and nearby
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.
Blackheath is around 7 miles from Westminster, and both are within our Greater London coverage.
We also cover nearby Greenwich (1 mile), Catford (2 miles), Eltham (2 miles).
What should you expect to pay in Blackheath?
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?
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.
Roof lantern resealing in Blackheath: 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 Blackheath?
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.
Can you match the colour of my frame?
We use sealants in common frame colours such as anthracite grey, black and white, and match as closely as the range allows.
How long does resealing take?
Most domestic lanterns take a few hours in dry weather.
Other lantern repairs in Blackheath
- Roof lantern leak repairs in Blackheath
- Glazing bar and capping repairs in Blackheath
- Upstand and kerb repairs in Blackheath
- Timber roof lantern repairs in Blackheath
- Leak investigation and inspection in Blackheath
- Commercial roof lantern repairs in Blackheath
Roof lantern resealing near Blackheath
More about roof lantern resealing · All roof lantern repairs in Blackheath