We carry out condensation diagnosis and fixes in Crawley and across the RH11 area. Condensation forms when warm, humid air meets a cold surface — and a roof lantern is the coldest surface in many kitchens.

Is it time for 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
Common causes we find
High humidity
Cooking, kettles, showers, drying washing and people all add moisture to the air.
Poor ventilation
Without trickle vents, extraction or an opening vent, moist air has nowhere to go.
Roof lanterns in Crawley
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.
Coastal wind drives rain hard against lanterns, so cappings and ridge seals on the seaward face take the most punishment.
Crawley is around 32 miles from Chichester, and both are within our West Sussex coverage.
Neighbouring places we cover include Horley (4 miles), Horsham (7 miles), East Grinstead (8 miles).
How much should it cost?
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 Crawley: questions
Do you cover Crawley?
Yes. We cover Crawley, including the RH11 postcode area, as part of West Sussex. 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.
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.
Other lantern repairs in Crawley
- Ridge and hip repairs in Crawley
- Upstand and kerb repairs in Crawley
- Solar control and self-cleaning glass upgrades in Crawley
- Leak investigation and inspection in Crawley
- Urgent leak make-safe in Crawley
- Roof lantern replacement in Crawley
Condensation diagnosis and fixes near Crawley
More about condensation diagnosis and fixes · All roof lantern repairs in Crawley