Many older conservatories have polycarbonate roofs that discolour, leak and are noisy in the rain. Replacing them with glass panels gives a clearer view, better sound and a longer life. Before you order, check the frame, choose the right glass and get the sizes exactly right.
Which glass goes in a conservatory roof
Glass above people's heads has to stay safe if it breaks. Roof panels for conservatories are normally sealed double glazed units with:
- a toughened outer pane, to take weather and impact,
- a laminated inner pane, so that if it breaks the pieces stay held together instead of falling into the room,
- a Low-E coating and gas filling to reduce heat loss,
- often a solar control or self-cleaning coating, because conservatory roofs overheat in summer and are hard to reach for cleaning.
Tell us the roof's direction and how the room is used. A south-facing conservatory usually needs stronger solar control than a north-facing one.
Check the frame can carry glass
Glass is much heavier than polycarbonate. A typical sealed glass roof unit weighs several times as much as a polycarbonate sheet of the same size. Before you change the roof, have the frame, glazing bars and supporting walls checked by a conservatory installer or structural engineer. Glazing bars made for 25 mm polycarbonate may also need adapting for a glass unit of a different thickness.
Building regulations
In England, a conservatory is generally exempt from building regulations if it is under 30 square metres, at ground level, separated from the house by external quality doors or windows, and has no fixed heating connected to the house. Changing a translucent roof for glass keeps it a glazed roof, which is usually treated differently from replacing it with a solid tiled roof. A solid roof normally needs building regulations approval. Confirm with your local building control before you start, especially if the conservatory is open to the house.
How to measure the panels
- Measure each existing roof sheet or each space between glazing bars, in millimetres.
- Note the thickness the glazing bars accept.
- Number each panel on a sketch of the roof, because panels at the hips and ends are often different shapes.
- Send us the sketch with sizes and shapes. Non-rectangular panels can be made to a template or drawing.
Glass, polycarbonate or a solid roof
| Polycarbonate | Glass | Solid tiled roof | |
|---|---|---|---|
| Light | Diffused, can yellow with age | Clear, with a view of the sky | Much less, unless rooflights are added |
| Rain noise | Loud | Quieter | Quiet |
| Heat in summer | Can be high | Depends on the coating chosen | Lower |
| Weight | Light | Heavier, frame must be checked | Heaviest, structure usually changed |
| Building regulations | Usually exempt | Usually exempt if the conservatory stays exempt | Usually needs approval |
Self-cleaning glass
Self-cleaning glass has a coating on the outer face that breaks down dirt in daylight and lets rain wash it off in sheets. It does not remove everything, and it works best on a roof with a reasonable pitch and regular rain, but it greatly reduces how often a conservatory roof needs cleaning. It is applied to the outer pane only.
Condensation and ventilation
Any glass roof can show condensation on the inside on cold mornings, especially in a room with plants, a tumble dryer or cooking. A Low-E coating and gas-filled units keep the inner pane warmer, which helps, but ventilation does the most: trickle vents, a roof vent or opening windows. Plan ventilation alongside the new roof.
How a roof replacement usually goes
- An installer checks the frame, the glazing bars and the base, and confirms that glass can be carried.
- The roof is measured panel by panel and a numbered sketch is made.
- The glass units are made to those sizes.
- The old sheets are removed and the glass is fitted, usually one section at a time, so the room is not left open for long.
Questions we are asked
Is a glass roof cooler than polycarbonate?
With the right solar control coating, a glass roof can let in far less of the sun’s heat than clear polycarbonate. Clear glass without a coating can make overheating worse.
Do you fit the roof?
We make and supply the glass. Fitting should be done by a conservatory or glazing installer who can check the frame.
Will a glass roof make my conservatory usable all year?
A glass roof with Low-E and solar control coatings is far more comfortable than polycarbonate, but a conservatory with large areas of glass will still be warmer in summer and cooler in winter than a solid-roofed room.
How heavy is a glass roof panel?
Glass weighs about 2.5 kg per square metre for each millimetre of thickness. A double glazed roof unit is several times heavier than a polycarbonate sheet, which is why the frame must be checked.
Send your roof sketch for glass roof panels made to size, or read toughened or laminated: which glass do I need?