Condensation forms when warm, humid air meets a cold surface — and a roof lantern is the coldest surface in many kitchens. Send photos from Barnet (EN5) and we'll tell you which it is — with the price agreed in writing before any work.

Signs you need condensation diagnosis and fixes
- Water on the inside of the glass on cold mornings, even without rain
- Black mould at the base of the lantern lining
- Wet window sills elsewhere in the house too
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.
About Barnet and the EN5 area
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.
From Westminster to Barnet is roughly 11 miles — all part of the Greater London area we cover.
Neighbouring places we cover include Potters Bar (3 miles), Borehamwood (3 miles), Finchley (3 miles).
Guide prices for condensation diagnosis and fixes in Barnet
Most condensation diagnosis and fixes jobs come in between £145 and £495 ex VAT (£174–£594 including 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?
Most lantern repairs in England need no approval at all. Where a job turns into a replacement, the Building Regulations 2010 apply and we confirm how the work will be signed off before we start. 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 Barnet: questions
Do you cover Barnet?
Yes. We cover Barnet, including the EN5 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.
Do you need to visit to price condensation diagnosis and fixes?
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.
What does a condensation visit cost?
Diagnosis visits start from £145 ex VAT. Any fixes are priced separately and confirmed in writing before work starts.
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.
Other lantern repairs in Barnet
- Roof lantern resealing in Barnet
- Flat roof junction and flashing repairs in Barnet
- Slipped glass panel repairs in Barnet
- Flat rooflight and skylight repairs in Barnet
- Roof lantern replacement in Barnet
- Commercial roof lantern repairs in Barnet
Condensation diagnosis and fixes near Barnet
More about condensation diagnosis and fixes · All roof lantern repairs in Barnet