A roof lantern leak is almost always a failed seal, a lifted capping, blocked eaves drainage or a problem where the kerb meets the flat roof — not a failed lantern. Send photos from Ammanford (SA18) and we'll tell you which it is — with the price agreed in writing before any work.

Signs you need roof lantern leak repairs
- Brown staining or bubbling paint on the plasterboard lining around the lantern
- Water running down the inside face of the glass
- A leak that only appears in wind-driven rain from one direction
Common causes we find
Failed silicone or glazing tape
UV and thermal movement break down the seal between capping, gasket and glass. Once a gap opens, water tracks along the bar and drops at the lowest point.
The kerb or roof junction
If the flat roof membrane isn't dressed high enough up the kerb, or the kerb has no fall, water sits against the joint and finds its way in under the lantern.
Covering Ammanford and nearby
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.
From Carmarthen to Ammanford is roughly 14 miles — all part of the Dyfed area we cover.
We also cover nearby Gorseinon (9 miles), Ystradgynlais (10 miles), Llanelli (11 miles).
What should you expect to pay in Ammanford?
Guide price for roof lantern leak repairs: £195–£595 ex VAT (£234–£714 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 Wales?
Straightforward repairs — resealing, gaskets, cappings, eaves and like-for-like parts — don't normally need building regulations approval in Wales. Replacing the whole lantern or enlarging the opening is different and falls under the Building Regulations 2010 (as applied in Wales); we confirm in writing which route applies before any replacement. Listed buildings in Wales need listed building consent from the local planning authority for alterations, with Cadw guidance on historic buildings; check with the council before changing a lantern on a listed property.
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 leak repairs in Ammanford: questions
How do I get a price for roof lantern leak repairs in Ammanford?
Send a few photos of the lantern and the problem, with your Ammanford 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 leak repairs?
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 a roof lantern leak repair cost?
Most leak repairs fall between £195 and £595 ex VAT for a standard lantern with ladder access. The fixed price is confirmed in writing before any work starts.
Do I need to be home?
If we need to water-test or check the inside of the lantern, yes. Exterior-only work can sometimes be done with access arranged in advance.
Other lantern repairs in Ammanford
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