The short answer
A roof lantern costs more than most other rooflights because it is a glazed structure, not a single pane. Typical UK market figures for a fitted roof lantern sit between £2,500 and £7,000. Treat it as a starting point, not a Ridgeway price. Size, frame material, glass, the upstand, the structure beneath and access push a job up or down, and the quote in writing comes after the survey.
What a roof lantern costs, as a starting point
Typical UK market figures for a roof lantern sit between £2,500 and £7,000. These are broad market figures for orientation only. A quote for your house comes after a survey, and it depends on the factors below.
If you want the site-wide picture across every unit type, the costs page sets the ranges side by side. This page deals only with what changes the cost of a lantern, so you can read a quote line by line.
Size and shape
Size is the first driver. A wider and longer lantern needs more glass, longer frame runs and heavier lifting. Shape counts too: a simple rectangular lantern with a single ridge costs less to make than a multi-faceted or hipped one, since each extra facet adds frame joints and glass panels.
Our guide to roof lantern sizes explains how the dimensions are set from the room and the roof opening.
Frame, glass and finish
The frame is usually aluminium, and the thickness of its sections, the number of glazing bars and the colour or finish all change the price. A two-tone finish, with one colour inside and another out, costs more than a single colour. Our aluminium roof lanterns guide covers frame choices.
Glass is the other large variable. Double glazing is the usual starting build. Moving up to triple, or adding solar control, self-cleaning or tinted layers, each lifts the figure on the unit. A laminated inner pane is a recommendation for a dwelling roof, not a requirement, and it adds a little to the price as well.
Upstand and structure
A lantern sits on an upstand, a raised kerb fixed to the flat roof. Where a good upstand is already in place, the work is lighter. Where a new one must be built and wrapped in membrane, it is an extra item on the quote. Our guide to flat rooflight upstands explains how they are built.
Structure below can be the biggest hidden cost. Lanterns are heavy. If the opening is larger than the existing roof timbers can carry, steel or new timbers may be needed to support it, and the question of steel support for a roof lantern comes up at the survey, not on the day.
Access, extras and paperwork
A lantern is lifted into place, sometimes by crane or by a team on scaffold. A narrow side passage, a roof high above the ground or limited space for scaffold affects how long the fitting takes and what equipment it needs. Opening vents, rain sensors or blinds add to the unit and are best specified at the start.
Paperwork has a cost as well. A new lantern is building work, so Building Control is notified; we handle that where the work is notifiable. If a permission application is needed, there is an application fee payable to the council.
| Factor | What it changes |
|---|---|
| Overall size | Glass area, frame length, lifting |
| Shape and facets | Number of joints and glass panels |
| Frame finish | Section size, colour, two-tone |
| Glass specification | Double or triple, coatings, tint |
| Upstand | New build or existing kerb |
| Structure and access | Steel, timbers, scaffold, lifting |
Where a lantern quote can go wrong
The usual surprise is the part nobody priced. A quote that covers the lantern but not the upstand, the steel or the scaffold looks cheaper until the missing lines appear later. Another is a lantern priced on a catalogue size that does not match the opening, so the opening has to change.
Two quotes can differ by a large sum because they describe different lanterns. Compare the frame section, the glass build-up and the inclusions before you compare the totals.
Cost of the lantern against cost of the roof around it
A lantern rarely arrives alone. It usually goes into a new extension or a re-covered flat roof, and the roof build-up around it, the insulation, the membrane and the trims, belong to the roof budget rather than the lantern line. Check that your quote says which of these it includes.
If the lantern is going onto a roof that already exists, the existing upstand and deck must be sound enough to carry it. That is a survey finding, and the answer on putting a lantern on an old flat roof explains what is checked.
Whether a bigger budget buys a better lantern
Not always. Extra money buys either more glass area or a better specification, and only the second improves how the lantern performs. A modest lantern with a good thermal break and sensible glass will outperform a larger one with a basic build.
So decide first what the lantern has to do. If it must light a dining area, size matters. If it must keep an extension comfortable in January, specification matters more. Our guide to choosing between a lantern and a flat rooflight helps if the budget is tight and a flat unit might do the job.
What a written quote should itemise
A quote you can compare line by line names the lantern size and the frame, the glass specification, the upstand work, any structural work, the access and lifting, the Building Control step, the making good inside and out, and what is excluded. A single lump sum hides the items you would otherwise question.
Ridgeway Skylights gives a free survey and a written quote. The job plan sent with it spells out the unit and its size, where permission stands, the Building Control route, the order wait and the fitting day. A ten-year guarantee stands behind our workmanship. For the wider service, see roof lantern installation and our answer on how long a lantern takes to fit.