If you have a flat-roofed extension, kitchen or garage conversion that feels a bit gloomy, roof glazing is often the fix. Flat roof windows, sometimes called flat rooflights or skylights, drop daylight straight down from above and can transform a dark room. Here is what they are, how they differ from a roof lantern, and how to choose.
A flat roof light is a glazed unit fitted into a flat or low-pitched roof to bring daylight in from overhead. Rather than looking out sideways like a wall window, it looks straight up at the sky, which makes it one of the most effective ways to light a room. Overhead glazing lets in noticeably more daylight than a vertical window of the same size, because it faces the open sky rather than being shaded by walls, fences and neighbours.
They are a popular choice for single-storey rear extensions, side-return kitchens, garage conversions and any flat-roofed space that could do with more light.
This is the question we get asked most, so let us clear it up.
A flat rooflight sits more or less flush with the roof, giving a clean, minimal look from both inside and out. The glass is usually a single flat pane or a gently curved unit. From inside you see a crisp square or rectangle of sky. From the garden, the roof stays low profile and modern. They suit contemporary extensions and situations where you do not want anything sticking up.
A roof lantern is a raised, pitched structure that rises above the roofline in a pyramid or ridged shape, with glazed sides as well as a top. It makes more of a feature, throws light in from several angles and gives a real sense of height and volume inside. Lanterns suit orangeries, larger extensions and anywhere you want a statement centrepiece. Our roof lanterns and flat roof lights page covers both if you want to compare them side by side.
In short: flat rooflights are subtle and minimal, lanterns are raised and dramatic. Both bring in lovely light; the right choice comes down to the look you want and how much headroom and roof space you have.
Whichever style you choose, roof glazing brings real advantages:
For a York extension that only gets side windows, a rooflight can be the difference between a room you use and one you avoid.
A few practical points are worth getting right:
Prices depend heavily on size, glass spec and whether the unit opens, so use these as a guide and get a quote. As of 2026, a good-quality fixed flat rooflight commonly starts in the few-hundred-pounds range for the unit and rises with size, opening mechanisms and premium glass, before fitting and any roof works. A roof lantern is typically a bigger investment again. For a real figure on your project, ask us for a quote and we will talk through the options.
A flat rooflight sits nearly flush with the roof for a minimal look, while a roof lantern is a raised, pitched structure that rises above the roofline and makes more of a feature.
Generally yes. Because they face the open sky rather than being shaded by walls and fences, overhead rooflights let in noticeably more daylight than a vertical window of the same size.
Yes. Rooflights come in fixed and opening versions, with manual or electric opening options, so you can add fresh air and let out heat if you want to.
The glazing work usually needs to meet current Building Regulations, and larger schemes can raise planning points. Rules change, so check the current requirements with your local authority before you start.
Not with the right glass. Modern units with solar control and low-e coatings manage heat and glare, keeping the room comfortable while still bright.
Thinking about opening up a flat-roofed room with more light? Download our latest brochure to see the options, or request a free quote and we will help you plan it.