The short answer
No, you cannot put tiles over an existing glass or polycarbonate conservatory roof. Tiles need a structure of rafters, battens and a membrane underneath them, and a glazed roof offers none of that. The glazing bars are not designed for the weight, and the sheets would crack or sag. A tiled conversion removes the old glazing and builds a new roof on the frame, strengthened where needed, and it needs a Building Regulations application.
Why tiles cannot sit on the old roof
A tiled roof is a system of layers. The tiles hang from battens, the battens are nailed across counter-battens or rafters, and a breathable membrane beneath them catches wind-blown water. The rafters carry all of it down to the walls. A glass or polycarbonate roof has none of these. It is held up by thin glazing bars made to carry a light sheet, and they are not strong enough for the weight of tiles, battens and insulation.
Laying tiles on top of the existing sheets would put the load on the sheets themselves, which would crack or flex. The tiles would also have nothing to fix to. Even if the roof held for a while, it would leak, and there would be no ceiling or insulation inside. This is a job that has to start with a strip-out.
What a proper tiled conversion involves
The sequence for a tiled conservatory roof is much closer to building an extension roof than to replacing glazing.
- Survey and design. We check the frame, the walls and the base, and design the roof to suit.
- Strip out. The old glazing, bars, cap strips and ridge come off.
- Structure. New rafters, or a strengthened frame, are fitted, often with steel at the eaves or in the walls.
- Weatherproofing. A breathable membrane goes over the rafters, then battens for the tiles, and flashings at the wall.
- Covering. Tiles or slates are fitted, with the ridge and verges fixed.
- Inside. Insulation, plasterboard, plaster and any lighting.
Our page on what happens when a conservatory roof is replaced goes through each stage.
The weight and the Building Regulations
A tiled roof is far heavier than glass. Even a lightweight system adds load to the frame, the dwarf walls and the foundations. That is why a solid roof on a former glass conservatory is notifiable, with building control asking for evidence that the structure can carry it. Our survey is where that starts. You can read the rules in our guide to conservatory roofs and Building Regulations. We handle the application where the work is notifiable.
Lighter alternatives to a full tiled build
If weight is the concern, lightweight tiled roof systems use a thinner build-up of insulated panels and fine-textured tiles, which reduces the load. They still replace the glazing and do not go over it. Some owners also consider insulation panels fitted under the existing roof to improve warmth without changing the outside. That is a different job, with different limits, and our page on insulating a conservatory roof compares panels with replacement.
Why shortcuts cost more later
We are sometimes asked for a cheaper way, such as fixing slates straight onto the polycarbonate, or boarding over the glass and covering that. These shortcuts fail for the same reasons. The boards have nothing to carry them, water gets between the layers and has nowhere to go, and condensation collects in the gap and rots whatever it touches. An unventilated void under a roof is how rot and mould begin. A properly built roof deals with moisture by design, with a membrane and ventilation, and that is the part that cannot be skipped.
What it costs
Typical UK prices for a solid tiled conservatory roof run from £6,100 to £15,000, or £650 to £1,200 per square metre. The figures include removing the old roof, because it has to go. Frame strengthening, roof windows and the finish inside change the total. The price you pay follows a survey, with a fixed written quote.
What we recommend if you want the tiled look
If you want a tiled roof, we start with the survey and photos, check the structure, and tell you whether the conservatory can take one. If the frame cannot, we explain the alternatives, and if the roof is sound we do not push you into a change you do not need. Ask your installer, whoever it is, to show you the rafter size, the spacing, the fixings and the tile weight per square metre in writing, so the load is something you can check rather than take on trust. Before you commit to anything, ask whether your structure was designed for tiles at all, because the answer shapes every other choice. The whole range is set out under conservatory roof replacement in Basingstoke. The site is cleared at the end, and the workmanship is guaranteed in writing for ten years.
Every roof is different. A free survey with photos settles it for yours.
Get a free survey