Roof lantern resealing in Cornwall | Roof Lantern Repairs

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. We carry out roof lantern resealing across Cornwall, with a guide price from your photos and a fixed price in writing before any work starts.

Sealant being applied along an anthracite aluminium roof lantern glazing bar

Signs you need roof lantern resealing

Cracked, split or shrunken sealant along the bars
Black mould or dirt lines trapped in old silicone
Sealant applied over sealant from previous patch repairs

What usually causes it?

Wrong product used

General-purpose or acetoxy silicone can fail early on some frames and coatings. Glazing joints need a low-modulus, compatible sealant.

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 Cornwall

Damp, mild winters keep moss and algae growing on flat roofs and lantern frames, which holds water against seals and blocks weep slots. Regular clearing makes a real difference in wetter areas.

Coastal wind drives rain hard against lanterns, so cappings and ridge seals on the seaward face take the most punishment.

What should you expect to pay for roof lantern resealing in Cornwall?

Guide price, per lantern£245–£495 ex VAT£294–£594 inc VAT

Guide price for roof lantern resealing: £245–£495 ex VAT (£294–£594 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.

Roof lantern resealing in Cornwall: questions

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.

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.

Which towns in Cornwall do you cover?

All of Cornwall, including Truro, Redruth, Falmouth, St Austell, Camborne, Newquay. Rural and remote addresses are covered by arrangement.

How do I get a price for roof lantern resealing in Cornwall?

Send a few photos of the lantern and the problem with your postcode, by WhatsApp or the form. We reply with a guide price and confirm the fixed price in writing before any work starts.

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