A kitchen extension with a flat roof is one of the best places for a rooflight. Light from above reaches the back of the room that windows cannot, falls straight onto worktops, and makes a deep extension feel open. A little planning makes the difference between a bright kitchen and one that is too hot, too cold or full of glare.
Where to put it
- Over the island or table. The most popular place. Light falls where people gather, and a long rooflight can follow the line of the island.
- Along the back of the extension. A rooflight close to the house wall brings light deep into the room and lights up the old back wall that lost its windows.
- Over the worktops. Good for task light, but avoid placing it directly above the hob, where steam and grease rise towards the glass.
- Away from where the TV or screens sit, to avoid glare.
Choosing the size
Start from the roof structure. Flat roof joists are often set at 400 or 600 mm centres, and a rooflight width that fits between them, or needs only one joist trimmed, keeps the building work simple. Then think about the room:
| Space | Sizes to consider |
|---|---|
| Small galley or utility room | 600 x 900, 600 x 1200, 800 x 800 mm |
| Over a kitchen island | 1000 x 2000, 1000 x 2500, 1000 x 3000 mm |
| Square dining area | 1000 x 1000, 1200 x 1200, 1500 x 1500 mm |
| Along a long extension | Two or three matching rooflights in a row |
See every size in our flat rooflight sizes guide.
One large rooflight or several smaller ones?
One large rooflight gives a strong, dramatic pool of light and an uninterrupted view of the sky. Two or three smaller ones spread the light more evenly along a long room and can be easier to fit between joists. Matching rooflights in a line also echo the rhythm of kitchen units below.
Heat, cold and condensation
- Heat in summer. Glass facing the sky gains a lot of heat. A south or west-facing kitchen benefits from solar control glass, or a blind.
- Heat loss in winter. Triple glazing loses less heat than double glazing, which matters on a roof. Our frameless flat rooflights are triple glazed.
- Condensation. Kitchens produce a lot of moisture. A good extractor hood, used while cooking, and some background ventilation keep condensation off the glass.
Before you order
- Agree the position and size with your builder, so the roof is framed for it.
- Build the kerb with a fall, so rain runs off the glass.
- Measure the finished kerb as shown in how to measure for a flat rooflight.
- Check the rules in do you need planning permission for a rooflight?
Light through the day
A rooflight lets in light from the whole sky, not just one direction, so even a north-facing kitchen gets bright, even daylight. On a south or west-facing roof, direct sun will move across the room through the day. Think about where that patch of sun will fall at breakfast, at lunch and in the evening, and whether you want it on the table, the worktop or the floor.
Glare on screens and worktops
Bright sun straight onto a glossy worktop, a television or a laptop can be uncomfortable. Placing the rooflight over the island rather than a work area facing a screen helps, as does a matt worktop finish near the rooflight. A blind gives control on the brightest days.
Blinds and shading
Integral blinds sit inside the glass unit, so they stay clean and never need dusting. Blinds fitted below the rooflight are easier to change later. Solar control glass reduces heat from the sun without a blind. On a south-facing kitchen roof, combining solar control glass with a blind usually gives the most comfortable room. Ask about solar control glass when you send your sizes.
Lighting at night
A large rooflight becomes a dark patch in the ceiling after sunset. Many kitchens add LED strip lighting inside the reveal around the rooflight, which lights the room and stops the opening looking like a black hole. Plan the cables before the ceiling is plastered.
Cleaning
A flat rooflight on a low roof is usually easy to reach with a long-handled brush and water. Leaves and dirt collect less on glass laid to a fall. Check how you will reach the roof safely before you choose a position over a high or awkward part of the building.
Questions we are asked
Do kitchen skylights make the room too hot?
They can on south and west-facing roofs in summer. Solar control glass, a blind and good ventilation keep the room comfortable.
Can a skylight go above the hob?
It is better not to. Steam and grease rise straight up; place the rooflight over the island or table and keep the hob under a solid ceiling with an extractor.
Should a kitchen rooflight open?
An opening rooflight helps ventilation. A fixed rooflight with a good extractor and a window or door that opens also works. Our frameless rooflights are fixed.
How big should a kitchen skylight be?
It depends on the room and the roof. A long rooflight such as 1000 x 2000 mm is popular over an island; two or three smaller ones spread light along a long extension.
Do I need planning permission for a kitchen skylight?
Often not, but it depends on the property. Our guide to planning permission for rooflights explains the usual rules in England.
Choose a size on our frameless flat rooflight page, or send us your kerb sizes.