How Much Does a Roof Lantern Cost in 2026? (UK)
A roof lantern in 2026 typically costs £1,600–£5,500 supplied and fitted, depending on size and frame. A small aluminium lantern starts around £1,600, a mid-size unit runs £2,500–£4,000, and a large or bespoke lantern can exceed £6,000. uPVC lanterns are cheaper but less slim; a flush rooflight is the budget alternative. Kerb building and structural openings add to the price.
How much is a roof lantern in 2026?
Typical 2026 UK roof lantern costs (supplied & fitted):
- Small aluminium lantern (1m x 1m) — £1,600–£2,600
- Mid-size (1.5m x 1m) — £2,500–£4,000
- Large (2m x 1.5m) — £3,800–£5,500
- Bespoke / very large (2.5m+ or double) — £5,500–£9,000+
Most homeowners adding a lantern to an existing flat extension roof spend £2,500–£4,500 fitted, including forming the kerb. If a new structural opening is needed, add £400–£1,200 for the timber or steel and Building Control.
Roof Lantern Cost by Size
Lantern price scales with glazed area and frame material. Aluminium gives slim, strong sightlines and is the most common; uPVC is cheaper but bulkier. All prices below are supplied and fitted onto an existing flat roof.
Small lantern — around 1m x 1m
Suits a small extension, utility or bathroom. A compact aluminium lantern with a kerb built onto the existing flat roof. One to two days.
Mid-size lantern — around 1.5m x 1m
The most popular size for a kitchen-diner extension. A good balance of light and cost, in aluminium with a grey or black frame and self-cleaning glass.
Large lantern — around 2m x 1.5m
A statement lantern flooding an open-plan extension with light. Larger glazed units are heavier, may need two fitters and stronger kerb support.
Bespoke or very large — 2.5m+ / double lanterns
Made-to-measure units, unusual shapes or a pair of lanterns over a big open space. Often need a steel or engineered kerb and structural sign-off.
What Actually Drives Your Bill
Beyond size, these factors decide where your lantern quote lands.
1. Frame material
Aluminium is stronger and slimmer, giving more glass and light, and costs more than bulkier uPVC. Most homeowners choose aluminium for the look.
2. Glazing spec
Standard double glazing is cheapest; solar-control, self-cleaning, triple or coloured-tint glass each add £150–£600 to the unit.
3. New opening vs existing
Dropping a lantern into an existing aperture is simple. Cutting a new structural opening in the roof adds £400–£1,200 for timber/steel and Building Control.
4. Kerb / upstand
A lantern sits on a builder's kerb. A pre-made GRP kerb is quick; a timber or steel kerb built to size takes longer and costs more.
5. Access & height
A single-storey extension roof is easy; a lantern over a first-floor flat roof needs scaffold and more lifting, adding to the labour.
6. Brand & guarantee
Premium brands such as Korniche, Atlas or Ultraframe cost more than budget lanterns but offer slimmer frames and longer warranties.
Roof Lantern Cost by UK Region
Based on a supplied-and-fitted mid-size aluminium lantern (1.5m x 1m) onto an existing flat extension roof, including kerb and flashing.
Real Project: Aluminium lantern over a kitchen extension, Guildford
A homeowner added a 1.8m x 1.2m grey aluminium lantern to an existing single-storey kitchen extension flat roof, building a new timber kerb and reworking the surrounding EPDM to make it watertight.
| Aluminium lantern unit (1.8m x 1.2m) | £2,350 |
| Form opening & trim rafters | £420 |
| Timber kerb & upstand | £380 |
| Re-dress EPDM & flashing | £290 |
| Labour (2 fitters, 2 days) | £680 |
| Total | £4,120 |
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