If a roof lantern pane looks cloudy or wet between the two layers of glass, the sealed unit has failed and moisture has got inside. Send photos from Northampton (NN1) and we'll tell you which it is — with the price agreed in writing before any work.

What you might be seeing
- Fog, droplets or white bloom between the panes
- One pane looks hazier than the others
- Misting that comes and goes with the weather
What usually causes it?
Edge seal failure
Every sealed unit has an edge seal and desiccant. Once the seal fails, humid air gets in and the desiccant saturates.
Movement and age
Thermal movement and age wear the seal; units at the bottom of the lantern often go first.
Roof lanterns in Northampton
Most inland lantern leaks aren't storm damage; they're usually tired sealant, a lifted capping or blocked eaves drainage. All three are quick to find and fix once you know where to look.
Close by, we also cover Wellingborough (9 miles), Daventry (12 miles), Rushden (12 miles).
How much should it cost?
Most misted glass unit replacement jobs come in between £245 and £595 ex VAT (£294–£714 including VAT), per glass unit. 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.
Misted glass unit replacement in Northampton: questions
Do you need to visit to price misted glass unit replacement?
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.
Which places near Northampton do you cover?
As well as Northampton, we cover nearby Wellingborough, Daventry, Rushden, Kettering and the rest of Northamptonshire.
How long does a replacement unit take?
Units are made to measure, so there's a lead time between measuring and fitting. Fitting itself is usually a short visit.
Will the new pane match the others?
We match tint and coatings as closely as possible; a new unit can look very slightly clearer than older neighbours.
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Misted glass unit replacement near Northampton
More about misted glass unit replacement · All roof lantern repairs in Northampton