In Swanley, as everywhere, 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 and we'll tell you what we think has failed.

What you might be seeing
- Cracked, split or shrunken sealant along the bars
- Several small leaks rather than one obvious one
- Sealant applied over sealant from previous patch repairs
What usually causes it?
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.
Wrong product used
General-purpose or acetoxy silicone can fail early on some frames and coatings. Glazing joints need a low-modulus, compatible sealant.
Covering Swanley and nearby
Sun and UV do more damage than rain on many lanterns here: brittle ridge caps, chalky finishes and hardened gaskets. They're cheap to replace before they let water in.
Coastal wind drives rain hard against lanterns, so cappings and ridge seals on the seaward face take the most punishment.
From Maidstone to Swanley is roughly 17 miles — all part of the Kent area we cover.
Close by, we also cover Bexley (3 miles), Dartford (4 miles), Welling (5 miles).
What should you expect to pay in Swanley?
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?
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.
Roof lantern resealing in Swanley: questions
How do I get a price for roof lantern resealing in Swanley?
Send a few photos of the lantern and the problem, with your Swanley postcode. We'll reply with a guide price and tell you whether a visit is needed before we can fix the price.
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.
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 Swanley
- Flat roof junction and flashing repairs in Swanley
- Misted glass unit replacement in Swanley
- Solar control and self-cleaning glass upgrades in Swanley
- Urgent leak make-safe in Swanley
- Roof lantern replacement in Swanley
- Orangery lantern repairs in Swanley
Roof lantern resealing near Swanley
More about roof lantern resealing · All roof lantern repairs in Swanley