Roof lanterns explained

A roof lantern is a raised glazed structure that sits on a flat roof, using pitched glass planes to admit daylight from multiple angles. Unlike a flat roof light — a single panel set flush into the deck — a lantern forms a visible architectural feature above the roof line, often becoming the centrepiece of an extension, orangery or kitchen diner.

How a roof lantern differs from a flat roof light

The distinction is structural and visual:

• Flat roof light — a sealed glazed panel installed in a prepared opening in the flat roof deck. Minimal or no visible height above the roof plane (frameless units sit flush internally).
• Roof lantern — a self-supporting glazed structure with sloping glass planes, ridge bar and eaves detail, raised above the flat roof surface.

Flat roof lights maximise daylight with minimal visual impact. Lanterns maximise daylight and create a focal point — the glazed volume is part of the room’s architecture.

Typical applications

Roof lanterns are specified where the design calls for a dramatic daylight feature:

• Orangery and garden-room extensions
• Kitchen diners in open-plan layouts
• Living areas where a flat panel would feel insufficient
• Commercial hospitality spaces — restaurants, bars and hotel atriums

They are less common in rooms where a low-profile solution is preferred — flat frameless roof lights or framed flat units suit those situations.

Construction and frame

Modern roof lanterns use thermally broken aluminium frames — the frame separates internal and external metal surfaces to reduce thermal bridging through the structure. Glazing bars divide the sloping planes into individual sealed glass units.

Layout options typically include:

• Four-pane — larger glass areas, fewer bars, contemporary appearance.
• Six-pane — more glazing bars, a traditional lantern aesthetic suited to period properties.

Pyramid lanterns — four equal sloping planes meeting at a central ridge point — are an alternative to the rectangular ridge-and-eaves form.

Glazing specification

Lantern glass planes use sealed double-glazed units with toughened outer panes. Inner pane options include toughened or laminated glass — a laminated inner pane adds safety and security for overhead glazing and is often preferred in residential applications.

Low-emissivity coatings and argon-filled cavities manage heat loss. Solar control coatings may be specified on south-facing installations to reduce overheating.

Sizing and bespoke options

Lanterns are available in standard sizes and made-to-measure configurations. The structural opening in the flat roof deck must be formed to the manufacturer’s setting-out dimensions — the same discipline applies as for flat roof lights.

For non-standard spans, pitches or linked multi-lantern layouts, a bespoke roof light consultation will confirm structural limits and frame options.

Roof lanterns vs roof lights: choosing between them

Factor

Flat roof light

Roof lantern

Profile above roof

Low or flush

Raised, visible

Daylight angle

Directly overhead

Overhead plus angled planes

Architectural impact

Minimal

Strong focal point

Cost

Typically lower

Higher — more frame and glass

Ventilation

Fixed or opening flat units

Usually fixed; separate vent may be needed

If the priority is discreet daylight with a clean ceiling finish, specify a flat roof light. If the priority is a statement feature that defines the room, a lantern is the better fit.

Installation considerations

Lanterns are heavier and more complex to install than single flat panels. The flat roof deck must support the lantern weight, and weathering at the eaves junction with the flat roof membrane requires careful detailing.

Confirm the upstand or kerb detail, structural opening size and any internal plasterboard lining requirements with the manufacturer before the deck is cut.

Every Vant Glass roof light is made to order in Britain, backed by a 20-year guarantee and free UK mainland delivery. Configure frameless or framed sizes in the online calculators or call 03330 902 592.