Condensation forms when warm, humid air meets a cold surface — and a roof lantern is the coldest surface in many kitchens. Send photos from Greenwich (SE10) and we'll tell you which it is — with the price agreed in writing before any work.

What you might be seeing
- Water on the inside of the glass on cold mornings, even without rain
- Drips after cooking, showers or drying clothes
- Black mould at the base of the lantern lining
Why it happens
Cold surfaces
Older glass, uninsulated kerbs and un-thermally-broken frames stay cold and collect condensation.
Poor ventilation
Without trickle vents, extraction or an opening vent, moist air has nowhere to go.
Covering Greenwich and nearby
Drier, sunnier parts of the UK are kinder to seals than the wet west, but strong sun ages sealant, gaskets and plastic end caps, and south- or west-facing lanterns can make rooms very warm. Solar control glass and an opening vent help.
Across London, many lanterns sit on rear extensions with access only through the house, so we protect floors and plan the work to keep time indoors to a minimum. Parking and any permits are factored into the quote.
Greenwich is around 6 miles from Westminster, and both are within our Greater London coverage.
Neighbouring places we cover include Blackheath (1 mile), Canary Wharf (2 miles), Catford (2 miles).
What should you expect to pay in Greenwich?
Typical range: £145–£495 ex VAT, which is £174–£594 with VAT, per visit. 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.
Condensation diagnosis and fixes in Greenwich: questions
Do you cover Greenwich?
Yes. We cover Greenwich, including the SE10 postcode area, as part of Greater London. Send photos by WhatsApp or the form for a free guide price, and we'll confirm the fixed price in writing before any work starts.
How do I get a price for condensation diagnosis and fixes in Greenwich?
Send a few photos of the lantern and the problem, with your Greenwich postcode. We'll reply with a guide price and tell you whether a visit is needed before we can fix the price.
Will new glass stop condensation?
Better glass raises the inner surface temperature and helps, but if the room is very humid, ventilation matters more. We'll tell you which will make the bigger difference.
Is condensation in a lantern normal?
Occasional light condensation on very cold mornings can be. Regular dripping isn't, and can damage linings and cause mould.
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Condensation diagnosis and fixes near Greenwich
More about condensation diagnosis and fixes · All roof lantern repairs in Greenwich