The short answer
It will be darker than a glazed roof, because daylight stops coming from above and arrives only through the side windows and doors. How dark depends on the size of the room, which way it faces and what you add. Fitting roof windows or glazed panels into the tiled slope sends daylight back down to the room's centre, and a pale ceiling adds to it.
A tiled roof trades some daylight for comfort. You can win a good share back, but only if you plan it before the roof goes on.
Why the room changes
A glazed conservatory is lit from every side and from above. Put a solid roof on and the overhead light is gone. What is left comes in through the walls, and the centre of the room, furthest from those walls, loses the most.
How much darker will it be?
There is no single answer, and nobody can give a fair percentage without seeing the room. A wide conservatory with glazing on three sides keeps plenty of daylight. A narrow one with a solid wall on one side and a high hedge on another can feel gloomy. A tall hedge, a neighbour's wall or a mature tree outside the window line can dim a room more than the roof ever did, so walk the room on a dull day and see where the gloom actually sits. The room's orientation matters as well: a south-facing room has a surplus of light to spare, while a north-facing one has none.
Many owners welcome the change. The glazing that made the room bright also left it sweltering in July and chilly in January, and our answer on swapping plastic for glass shows the other route. The question to settle is how much light you want against how much comfort.
Roof windows: the usual fix
Here a roof window means a window with its own frame, built into the pitch of the roof. It lights the middle of the room, and an opening one adds ventilation.
How many do I need?
That depends on the size and shape of the room. A small room may be well served by one or two, and a large one by a row. Putting them high on the slope, away from the house wall, lights the floor further in. The framing, flashing and tiling around each one are part of the roof build, so the openings are planned with the roof, not cut afterwards.
Under Part L, roof windows are held to the window figure, 1.4 or a Band B window energy rating, and a roof built new needs Building Regulations sign-off, as our answer on fitting roof windows in a solid conservatory roof explains. For scale, MyJobQuote lists a standard mid-range roof window at £1,100 (Sep 2026), before the framing work around it.
Glazed panels and lanterns in a solid roof
A roof window is not the only way to bring light back. A glazed panel can be built into the roof as a section of the roofing, and a lantern, a raised glazed feature with its own small pitched or flat top, can sit on the ridge area or over a flat section of the structure.
Is that better than separate windows?
It can be, in a room where you want one bright centre rather than several small openings. A glazed panel keeps the skyline simple and puts light exactly where you sit. The glass still has to be specified properly, and its junction with the tiles needs lead or a purpose-made flashing. It also adds to the cost, because it is a glazing component inside a roofing job. The more glass in the roof, the more heat it lets in on a sunny day, so the light you recover is a balance against the comfort you wanted.
This is where the choice of trade matters, and our answer on a roofer or a glazier says who should be responsible for each joint when both are involved in the same roof.
Making a solid-roofed room feel bright
Light inside the room is also a matter of what it falls on. A pale, matt ceiling bounces what arrives back into the room, and a dark one soaks it up. Plain walls in light colours and a floor that is not very dark do more than most owners expect, and mirrors opposite the windows carry daylight further in.
Should I keep the glazed roof if light matters most?
If the room is north-facing and daylight is what you want from it, a new glazed roof may serve you better than a solid one. If summer heat and winter cold are what stop you using the room, a solid roof with good windows is worth the trade. The deciding factors are how you use the space and how it faces.
At the survey we stand in the room, note the aspect and the dark corners, and the written total covers the roof and whichever windows you settle on. A picture of the existing roof and the room dimensions are enough to start the conversation. For the overall choice, see our conservatory roofs page.
More on daylight under tiles
Can I add roof windows after the solid roof is built?
It can be done, but it is harder. The tiles, battens, insulation and ceiling have to be opened up, the rafters trimmed and the flashings built in. Planning the windows with the roof gives one set of works and tidier results, so raise them when we first talk about a tiled roof.
Will spotlights and wall lights fix a dark room?
They help in the evening, but they do not replace daylight in the daytime. A conservatory is usually chosen for the feel of natural light. If the room feels gloomy at midday, roof windows or glazed panels solve it, while lighting makes the evening better.
The full picture: Conservatory roofs in Taunton · More short answers