How Much Does a New Roof Lantern Cost in 2026? (UK)
In 2026 a roof lantern costs from around £400 supply-only for a small uPVC unit to £2,000–£4,000+ for a large bespoke aluminium lantern. Fitted into an existing flat roof, a standard size typically lands at £1,500–£4,000 all-in once the opening, upstand and glazing are done — rising for oversized units or where new structural support is needed. Size, frame material and glazing spec are the big price drivers.
Planning the work? Check what it usually costs, or work out your own estimate. The free quote form is at the top of this page.
Roof lantern cost — the short answer
- Small uPVC lantern (approx 1m × 1m), supply: £400–£900.
- Mid-size aluminium lantern (approx 1.5m × 1m), supply: £900–£1,800.
- Large or bespoke aluminium lantern, supply: £2,000–£4,000+.
- Fitted into an existing flat roof (standard size): £1,500–£4,000 all-in.
- Biggest cost drivers: size, frame material, glazing spec and whether structural work is needed.
The lantern itself is only part of the bill. On a flat roof you also pay for forming the opening, building a timber upstand, flashing and making good — so the fitted total is usually well above the supply-only price, especially if the roof structure needs strengthening.
Roof Lantern Cost by Size and Material (UK 2026)
Indicative supply prices, plus a typical fitted total. Inc. VAT.
Fitting a lantern into a brand-new extension roof is usually cheaper per unit than retrofitting one into an existing roof, because the opening and upstand are built in from the start.
What Moves a Roof Lantern Quote Up or Down
Size & glazing area
Bigger lanterns need stronger frames and heavier glass, so price climbs steeply with span — a 3m unit costs far more than two small ones.
Frame material
Slim powder-coated aluminium frames cost more than uPVC but give bigger glass and a sleeker look, which is why they dominate modern extensions.
Glazing specification
Double vs triple glazing, solar-control or self-cleaning glass and a low U-value all add cost but improve comfort and reduce glare and heat loss.
Structural & making good
Forming the opening, building the upstand, flashing and any new beams or trimming joists add labour — the hidden costs that separate supply-only from fitted.
Common Questions
Related Guides
More cost and planning guides for your roof and extension project.
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