Buying Guides · 4 min read
Guide to Rooflights
How to think about rooflights before you order one: type, placement, glass, ventilation and realistic costs, written as impartial advice.
Rooflight Ideas: Positioning, Style and Detailing
A rooflight is a small element with a large effect on a room. Positioning and detailing it well makes the difference between a genuine feature and an afterthought.
4 min read
Rooflights are often specified late in a design process — added to a flat roof extension almost as a standard item, in a standard size, in the middle of the ceiling. Positioned and detailed with more thought, a rooflight can transform how a room feels through the day, tracking light across a wall, illuminating a stair, or framing a piece of sky rather than simply brightening a kitchen.
This guide covers rooflight styles, positioning strategy and the details that separate a well-considered rooflight scheme from a standard one.
Flat rooflight or lantern
| Style | Character | Typical cost |
|---|---|---|
| Flat rooflight | Minimal, flush with the roof, clean sightlines from inside | £1,200–£4,000 supplied, size dependent |
| Lantern rooflight | Adds height and a sense of volume, more traditional reference | Generally higher than an equivalent flat rooflight |
| Rooflight strip (series of flat units) | Even light along a run, good for deep-plan extensions | Priced per unit, scales with length |
Where to position a rooflight
Rooflights are most effective when positioned to solve a specific lighting problem or highlight a specific feature, rather than simply centred in a room. A rooflight over a stairwell brings daylight down through a typically dark part of the house; one positioned to track sun across a feature wall through the day creates a changing quality of light that a standard window cannot.
- Over a kitchen island or worktop, for task lighting without overhead artificial light during the day
- Above a stairwell, to bring daylight into what is often the darkest part of a house
- Along the back of a deep-plan extension, where wall glazing alone cannot reach the rear of the room
- Positioned to avoid roof structure — check truss or joist positions with the structural engineer before finalising placement
Kerb and upstand detailing
The kerb (or upstand) is the raised frame the rooflight sits on, needed for weathering and insulation. A kerb that is taller than necessary is one of the most common rooflight complaints, since it becomes visible from inside as an unwanted deep reveal. Agreeing kerb height with the roofer and rooflight supplier together, based on the specific insulation build-up, avoids this.
Opening vs fixed rooflights
A fixed rooflight is simpler and cheaper; an opening (electric or manual vent) rooflight provides ventilation and can help purge heat from a room that overheats in summer — a genuine consideration for a heavily glazed kitchen extension. Electric opening rooflights with rain sensors add convenience but also cost and maintenance.
- Consider at least one opening rooflight in any large glazed kitchen extension for summer ventilation
- Weigh electric vs manual opening against how often the rooflight will realistically be reached and operated
- Check solar control glass specification on any large rooflight — overhead glazing receives more direct sun than a vertical window
What to avoid
- Avoid an oversized kerb or upstand that creates an unnecessarily deep internal reveal
- Avoid positioning a rooflight without checking the roof structure below, which can force an awkward last-minute repositioning
- Avoid standard clear glass on a large rooflight above a room that already gets strong sun — heat gain from overhead glazing is more pronounced than from vertical glazing
- Avoid a single centred rooflight as a default when an off-centre or strip arrangement would better solve the room's actual lighting needs
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