Roof Lantern Cost by Size (1m x 1m to 4m x 2m) in Cheltenham

As a 2026 UK guide, roof lanterns range from around £2,000 for a 1m x 1m unit to £8,000 or more for a 4m x 2m lantern, supplied and fitted. Size is the single biggest factor in the price, but it is not the only one. The accurate figure for your roof is a fixed written quote after a free survey.

This page sets out indicative ranges by size so you can find the row that fits your extension. Treat these as a starting point, not a final price.

Roof lantern cost by size (2026 guide)

• 1m x 1m: £2,000–£3,000 supplied and fitted
• 1.5m x 1m: £2,600–£3,800
• 2m x 1m: £3,000–£4,400
• 2m x 1.5m: £3,600–£5,200
• 3m x 2m: £5,000–£7,500
• 4m x 2m: £7,000–£8,500+

These are indicative figures covering the lantern, flashing and our installation labour, assuming a builder-formed kerb and reasonable single-storey access. A new insulated upstand or structural work is priced separately at survey.

Why size moves the price so much

More glass and framework

A larger lantern needs more glazing panels and more aluminium. Wider spans also need additional rafter bars for strength, which adds both material and weight.

Handling and access

Bigger units are heavier and need more care, and sometimes more people, to lift and seat safely. That feeds into labour.

The kerb scales too

A larger aperture means a larger kerb. If a new insulated upstand is needed, its cost rises with size as well.

Beyond size: other cost factors

Glazing specification

Solar control, self-cleaning, acoustic or triple glazing all add cost across every size. On a large south-facing lantern, solar-control glass is often worth it for comfort. See our energy-efficient skylight page.

Frame finish and sightlines

Slimmer profiles and bespoke or dual colours carry a modest premium over standard finishes.

Roof and access

Lanterns at height or with awkward access may need scaffolding, which adds to the total regardless of size.

Choosing the right size for your local extension

Picking a lantern size around Cheltenham and the Cotswolds is as much about the proportions of your extension as it is about budget, and the local housing stock tends to push toward certain sizes. On the typical single-storey rear kitchen extension across the Cheltenham semis — Hatherley, Up Hatherley, Warden Hill, Charlton Kings — a 2m x 1m or 2m x 1.5m lantern is the sweet spot, large enough to flood an open-plan kitchen-diner with light without overwhelming a room of that footprint. The bigger 3m x 2m feature lanterns we fit tend to go on the more generous detached properties and the larger new builds around Bishop’s Cleeve and the edges of Tewkesbury and Gloucester, where the extension itself is wider and there is room for a real centrepiece.

There is a practical local point on the larger sizes. A 3m x 2m or 4m x 2m lantern is a heavy, awkward lift, and on a Cheltenham terrace or a tight Cotswold-village plot where the only route to the rear is through the house or down a narrow passage, the access can matter as much as the dimensions. On the open-plan new estates, by contrast, a big lantern often goes straight over the side and lands easily. We always weigh the size against the access at survey, so the figure you get reflects your actual plot, not just the row in the table.

A note on building control and setting

Whichever size you choose, the building control body depends on your address — Cheltenham Borough, Tewkesbury Borough, Cotswold District or Stroud District. On a rear extension out of public view a lantern of any size is rarely a planning issue, but in a Cotswold-stone village or a Cheltenham conservation area, a very large, prominent lantern can attract more scrutiny than a modest one. Right-sizing for the setting is sometimes the smartest spend.

Worked examples

Example 1 — compact lantern. A 1m x 1m double-glazed lantern on an existing kerb. Indicative total around £2,200–£2,800.

Example 2 — large feature lantern. A 3m x 2m lantern with solar-control glazing and a new insulated upstand. Indicative total around £5,800–£7,200.

Example 3 — mid-size on a Cheltenham semi. A 2m x 1.5m double-glazed lantern over a rear kitchen-diner on an existing builder kerb, good side access. Indicative total around £3,800–£4,800.

These figures set expectations only. The accurate number is the fixed written quote after survey.

Ways to keep the cost sensible

• Right-size the lantern. The largest size is not always the best fit for the room or the budget.
• Form the kerb during the build. An accurate builder-formed upstand avoids rework.
• Target glazing upgrades. Concentrate solar-control glass where the sun is strongest.
• Share access. Book while scaffolding is up for other works.
• Weigh size against access. On a tight terrace plot, a slightly smaller lantern can be the more economical choice once handling is factored in.

Why the quote matters more than the guide

Size points you to the right range, but kerb, glazing, finish and access decide the real price. We survey your roof for free, then give you a fixed written quote, backed by our written guarantee on our workmanship.

See our roof lantern installation page for the full picture, compare with the headline roof lantern cost guide, or get a quote for your fixed price after a free survey.