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.
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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