Why a solid roof needs a skylight at all
With a clear roof, the brightest light in a conservatory comes from straight above. Swap that roof for insulated panels and all the daylight has to come in through the walls. Near the windows, you will hardly notice. At the back of the room, against the house, it can feel dim, especially on a grey afternoon in November.
A glazed roof light fixes that spot without giving back the heat problem. It is a small area of glass in a big area of insulation, so the room stays warm while the dark corner gets its sky back.
What you are buying
- Glazed roof light, £395 each. A sealed glazed unit built into the panel layout in place of a section of panel, fitted and sealed on the same day as the rest of the roof.
- LED spotlights, £345. Slim lights set flush into the white underside of the panels, for the evenings and dark winter days.
Both are fitted by the same team on the same visit, so they add little or no time to the job. Plan them at survey, because the roof light positions are built into the panel sizes before anything is made.
Five rules for placing a roof light
- Put it where the room is darkest. That is nearly always the strip closest to the house wall, furthest from any window.
- Put it above where you sit or eat. Light falling on a table or the end of a sofa is light you notice.
- Keep it off the television wall. Direct sun through a roof light onto a screen is worse than having none.
- Think about which way it faces. A roof light on a south facing slope lets in more sun, and more summer warmth, than one facing north.
- Keep it away from the gutter. A roof light low down near the eaves lights the window sill, which already has light. Higher up, near the ridge or wall plate, does more good.
How many, by roof size
This is a starting point. Your survey will look at the windows, the direction the room faces and how you use it.
| Roof | Typical size | Roof lights to start with | Cost of lights |
|---|---|---|---|
| Small lean-to, under 2.5 m deep | up to 12 m² | None, or 1 | £0 to £395 |
| Deeper lean-to or small Edwardian | 10 to 15 m² | 1 | £395 |
| Medium Edwardian or Victorian | 15 to 25 m² | 1 to 2 | £395 to £790 |
| Gable end | 12 to 25 m² | 0 to 2 | £0 to £790 |
| Large P-shape | over 25 m² | 2 to 3 | £790 to £1,185 |
Placement by roof style
Lean-to
One roof light a short way down from the wall plate, roughly central along the length. On a long lean-to over about 5 m, two spaced evenly along the house wall. More on the lean-to page.
Edwardian
One on each side face, close to the ridge, balances a square room. On a small Edwardian, one on the side face that gets less sun is often enough. See the Edwardian page.
Victorian
The bay facets taper towards the top, so they are too narrow for a good roof light. Use the wider side slopes at the back of the roof instead, which is also where the room is darker. See the Victorian page.
Gable end
The glazed triangle at the front lets plenty of daylight in, so many gable ends manage without one. If the back of the room feels dim, a roof light on each slope, set close to the house wall. See the gable end page.
P-shape
The lean-to leg is the darker, narrower end, so that is where the first one or two go. A deep projecting section can take one more on a side slope. See the P-shape page.
The trade-off, in numbers
A roof light is glass, so it loses more heat than the panel it replaces. That is the honest cost of daylight. The good news is that it is a small patch. On a 17 m² Victorian, two roof lights take up a small share of the roof, and the rest is 0.43 panels. The room still loses far less heat through the roof than it did under 16 mm polycarbonate at 2.3.
Roof lights are included in the specification we agree with building control, since Approved Document L sets limits for roof windows as well as roofs. We handle that as part of the application.
Worked example
A medium Victorian of about 17 m², with two roof lights on the back slopes and LED spotlights:
- Roof: £4,350 to £5,150
- Two roof lights: £790
- LED spotlights: £345
- Total: about £5,485 to £6,285 fitted
Try your own combination in the roof builder.
Spotlights for the dark months
Even with roof lights, a conservatory in December is dark by half past four. LED spotlights set into the white ceiling give an even light that reflects off the panels, with nothing hanging down. They suit low roofs especially well, such as on a bungalow conservatory, where there is no height for a pendant. We talk through where the power comes from and where the switch goes at survey.
Fresh air is a separate job
People sometimes expect a roof light to ventilate the room. Plan ventilation through your windows and doors instead, and read our guide on conservatory ventilation if the room gets stuffy. For everything else about the roof itself, go back to the insulated conservatory roof overview.
Questions
Where should a skylight go in a solid conservatory roof?
Where the room is darkest, which is almost always close to the house wall. Place it above where you sit or eat, away from the television, and higher up the slope rather than near the gutter.
Can a skylight go in one of the bay facets of a Victorian roof?
It is not a good spot, because the facets narrow towards the top. We put roof lights in the wider side slopes at the back, which is also where the room needs light most.
Do skylights undo the insulation of a panel roof?
A little, because glass loses more heat than a 0.43 panel. One or two are a small share of the roof, so the room still keeps far more heat than under polycarbonate.
How much are a roof light and spotlights together?
One glazed roof light is £395 and LED spotlights are £345, so £740 for both, fitted on the same visit as the roof.
