How to Choose the Right Roof Lantern

Consider the style of your home

A roof lantern should feel like a natural part of the property rather than an addition that has been considered in isolation.

Traditional homes, period properties and orangeries often suit roof lanterns with classic proportions, painted timber interiors and more traditional glazing-bar layouts.

Contemporary extensions often favour cleaner lines, larger areas of glass and fewer rafters. Aluminium roof lanterns are particularly suited to this style because they can provide slim sightlines and a more minimalist appearance.

There is also plenty of middle ground. A traditional glazing pattern can be combined with aluminium construction, while a timber-framed lantern can be designed with fewer rafters for a cleaner appearance.

Choose the right proportions

The size of a roof lantern has a significant influence on both the appearance of the room and the amount of natural light it receives.

Rather than choosing a lantern according to a fixed formula, consider the proportions of the room, the available roof area and the relationship between the lantern and the surrounding solid roof.

A lantern that is too small may feel lost within a large extension, while one that occupies almost the entire roof can dominate the space and increase the amount of solar gain.

The position of structural supports, roof construction and the arrangement of furniture or kitchen units below can also influence the most appropriate size and position.

Standard or made to measure?

Standard-size roof lanterns can be a very practical choice where the dimensions suit the project. They are generally straightforward to specify and may offer shorter lead times and more economical pricing.

A made-to-measure roof lantern becomes useful where the opening is an unusual size, where particular proportions are required or where the architectural design calls for a non-standard shape, pitch or glazing arrangement.

If you are still at the design stage, it can be worth considering the available standard sizes before the roof opening is finalised. This can sometimes simplify both specification and cost.

For more unusual projects, see our made-to-measure roof lanterns.

Timber or aluminium?

Material affects the appearance, detailing, maintenance and cost of a roof lantern.

Our timber collections use painted Sapele hardwood internally with aluminium capping externally. This provides the warmth and detailing of timber within the room while protecting the exterior from direct exposure to the weather.

Aluminium roof lanterns create a cleaner, more contemporary appearance and require relatively little maintenance. Their slim profiles work particularly well where larger areas of glass and minimal framing are preferred.

Neither material is automatically better. The right choice depends on the architecture of the property and the appearance you want to achieve.

Read our timber vs aluminium roof lantern guide →

Consider the rafter layout

The number and arrangement of glazing bars can make just as much difference to the appearance of a roof lantern as the material itself.

Traditional designs generally use more rafters and smaller panes, creating a more detailed architectural appearance. Contemporary designs often reduce the number of rafters to produce larger uninterrupted areas of glass.

At Just Roof Lanterns, our collections range from the more traditional multi-rafter appearance of Classic to the reduced framing of Linear and the deliberately minimal appearance of Urban. Hybrid uses aluminium construction with a more traditional glazing arrangement.

When comparing roof lanterns, it is therefore worth looking beyond the frame material and considering the overall glazing pattern.

Choose the right glazing

The glass specification affects natural light, solar gain, glare and thermal performance.

High-performance double glazing is standard across our principal roof-lantern ranges, with solar-control, low-emissivity and self-cleaning options available depending on the system.

Solar-control glazing can be particularly useful for larger lanterns or rooms receiving strong direct sunlight because it helps reduce solar gain and glare. In more shaded locations, maximising light transmission may be the greater priority.

The Ug-value describes the insulating performance of the glass unit itself: the lower the figure, the better the insulating performance. It should not, however, be confused with the thermal performance of the complete roof lantern, which also depends on the frame, glazing bars and thermal breaks.

Because a roof lantern is overhead glazing, the safety specification should also be considered. Toughened and laminated glass behave differently if broken, and laminated inner panes may be specified where retaining the glass after breakage is particularly important.

Explore our roof lantern glazing guide →

Ventilation and comfort

A roof lantern can introduce a significant amount of daylight, but comfort also depends on how the room is ventilated.

Opening roof vents can help warm air escape and encourage air movement, particularly during warmer weather. Manual and electrically operated vents are available on selected designs.

Ventilation and solar-control glazing perform different roles. Solar-control glass helps manage solar gain and glare, while opening vents allow warm air to escape.

The overall ventilation requirements of an extension should still be considered as part of the building design rather than relying on roof-lantern vents alone.

Read our roof lantern ventilation guide →

Planning permission and Building Regulations

A roof lantern does not necessarily require a separate planning application, particularly when it forms part of an extension being constructed under permitted development rights. However, this will depend on the property and the wider work being carried out.

Listed buildings, conservation areas and properties where permitted development rights have been restricted may require additional consideration.

Planning permission and Building Regulations are separate matters. Even where planning permission is not required, an extension will normally still need to satisfy relevant Building Regulations requirements relating to areas such as thermal performance, structure, ventilation and safety glazing.

Highly glazed extensions can also require additional thermal calculations, depending on the amount of glazing included in the design.

Your architect, building designer or Building Control body should confirm the requirements for the individual project.

Read our Building Regulations and glazed extensions guide →

Installation and roof preparation

A roof lantern needs to be installed onto a correctly prepared structural kerb or upstand.

The supporting kerb should be square, level and structurally suitable for securely fixing the roof lantern. Accurate dimensions are particularly important because different systems use different measurement conventions.

Our timber collections are generally specified using the internal kerb opening, whereas our aluminium collections generally use the finished external kerb size.

Builders should therefore work from the upstand information or approved drawing provided for the particular lantern rather than assuming that the same setting-out dimensions apply to every system.

For installations arranged through Just Roof Lanterns, our normal kerb requirement is a minimum of 100mm wide and 150mm high, unless otherwise agreed for the particular roof-lantern system or project.

View our roof lantern kerb and upstand guidance →

Budget and specification

The cost of a roof lantern will depend on more than its overall dimensions.

Material, glazing specification, colour, opening vents, rafter arrangement and whether the lantern is standard or made to measure can all influence the final price.

Timber-framed lanterns will generally cost more than a comparable standard aluminium design because of the hardwood materials, joinery and finishing involved. Standard aluminium lanterns can therefore provide a particularly cost-effective option where their sizes and styling suit the project.

It is worth comparing the complete specification rather than simply comparing headline prices. Two roof lanterns of similar dimensions may include different glazing, finishes or design features.

Which roof lantern is right for you?

There is no single roof lantern that is right for every property.

A traditional home may benefit from the warmth and detailing of a timber-framed lantern, while a contemporary extension may suit the slimmer sightlines of aluminium. A sunny room may benefit from solar-control glass, while a shaded extension may place greater emphasis on maximising daylight.

The most successful choice comes from considering the property, room proportions, material, glazing, roof preparation and budget together.

You can browse our full range of roof lanterns to compare the available designs, or contact us if you would like help choosing an appropriate roof lantern for your project.