A 3m x 2m aluminium roof lantern in Ipswich and Suffolk typically costs between £6,200 and £8,400 supply-and-fit, on a single-storey extension with a sound structure and reasonable access. That figure covers a thermally broken aluminium frame, solar control double glazing, a new insulated kerb, all fixings, weathering and internal trims. It assumes no structural upgrade is needed and the roof can already carry the opening. Add structural work, difficult access or a glazing upgrade and the number rises from there.
That is the headline for the single most-asked size, because 3m x 2m suits a typical open-plan kitchen diner. Below is what makes up the figure and the assumptions it rests on, so you can see whether a quote you have been given is complete. This sits under our main roof lantern installation page.
What the 3m x 2m figure includes
At 3.0 x 2.0m an aluminium lantern glazed in double units weighs somewhere around 250kg to 320kg, carried on four or five glazing bars a side and a full-perimeter eaves beam. The supply-and-fit range assumes our default specification: a polyamide thermal break in the frame, a solar control coated double unit with a warm-edge spacer and argon fill, and a toughened outer with a laminated inner pane, which is not optional on overhead glazing.
| Line item | Typical range |
|---|---|
| Aluminium unit, solar control double glazing | £3,800 to £5,200 |
| New insulated kerb and weathering | £900 to £1,500 |
| Fitting labour and access, single-storey tower | £1,000 to £1,600 |
| Internal making good and trims | £300 to £600 |
| Disposal | £150 to £300 |
| Typical supply-and-fit total | £6,200 to £8,400 |
The unit itself is the biggest single number, and it scales with glazed area and glazing specification rather than a flat rate per square metre. The line items above are folded into one fixed figure on the quote; we itemise them here only so you can see there is nothing hidden. The full method behind this breakdown is on our roof lantern cost page.
The assumptions the price depends on
Every figure above rests on four assumptions. Change any of them and the number moves, sometimes a lot.
- The structure already carries the opening. A 3m x 2m opening is well beyond the 1.5m point where a ring beam and a structural engineer’s calculation become necessary. On a new extension the ring beam is usually in the structural drawings already, so its cost sits in the build, not the lantern. On a retrofit into an existing flat roof it is almost never there, and the ring beam is the single biggest add-on, quoted separately once the engineer’s design is confirmed.
- Access is straightforward. The range assumes a single-storey extension a tower can reach. Two-storey access, a restricted side passage, or a roof needing full scaffold rather than a tower changes the access line considerably. At this size, on an awkward roof, a glass lifter or extra labour for the lift is sometimes needed too.
- Standard specification. Aluminium, double glazing, single colour. A timber frame adds 40 to 70 per cent, triple glazing adds 15 to 25 per cent on the unit, a dual-colour finish adds £250 to £500, and an electric opening vent, which a south-facing 3m x 2m lantern often wants, adds £600 to £1,100 fitted.
- Inland, not open coast. Within a mile of open sea at Felixstowe, Harwich or Aldeburgh we fit marine-specification coatings and 316L stainless fixings as standard, which adds a modest amount. Estuarine towns like Woodbridge carry moderate salt loading and a lighter upgrade. See coastal corrosion of roof lanterns for what changes.
A 3m x 2m lantern is where structure stops being optional. At this width the opening always needs proper structural framing. On a new build that is already priced into the extension. On a retrofit it is the line most likely to be missing from a low quote, so if a 3m x 2m retrofit price looks cheap, check whether the ring beam is in it.
Where this size sits against others
A 3m x 2m lantern is at the upper end of standard catalogue sizes. Above it you are usually into a structural upgrade, a crane lift, or a multi-section lantern with a structural spine, all of which change the price materially and are decisions to make before the roof is built. Our page on large-span roof lanterns covers what happens beyond this size. For proportion, a 3.0 x 2.0m lantern suits a room of roughly 30 square metres of floor, sitting in the 15 to 20 per cent glazing band we aim for, which our roof lantern size guide explains.
Related questions
- How much does it cost to replace an existing roof lantern? if you are swapping an old one out.
- Is an aluminium roof lantern cheaper than timber? for the frame-material comparison at this size.
- Roof lantern or flat rooflight? if you are still choosing the product.
Get the exact number for your roof
The ranges above become a single fixed figure once we have surveyed your roof, checked the structure and confirmed access and orientation. That price does not move unless you change the specification. Request a fixed quote for a 3m x 2m roof lantern in Ipswich, Suffolk or north Essex, or see published prices across every size and service first.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.