A solid conservatory roof is any roof that is opaque and insulated, put on in place of glass or polycarbonate. Inside, it becomes a plastered or boarded ceiling. Outside, it looks like a small roof, usually in tiles, slate or a tile-effect sheet. The change is bigger than it sounds. A conservatory with a glazed roof behaves like a greenhouse attached to the house, hot when the sun is out and cold when it is not. Take the glass away and put a properly built roof in its place, and the room starts to behave like the rest of the home. This guide explains the two main ways of building a solid roof, what each is made of, what the frame has to carry, and how to keep daylight in a room that has just lost its glazed ceiling. Costs and approvals have their own guides, which we link where they matter.
What counts as a solid roof
The phrase covers a family of roofs, not a single product. What they share is a closed build-up, working from the outside in: a weathering layer, a waterproof membrane, insulation, and an internal lining. What differs is the weight of that build-up and how it is carried.
The first kind is the full tiled roof, built from timber rafters in much the same way as the roof of the house. The second is the lightweight warm roof, in which panels with an insulating core, or thin sheets pressed to look like tile, do the same job for far less load. Both replace a roof that was mostly sheet or glass, and both give a room that stays steadier in temperature. Twin-wall sheet and double-glazed units simply cannot hold as much insulation as a solid build-up, and that is the physical reason the room changes character.
Some people also consider a hybrid: a solid roof with one or more roof windows or a lantern let into it, to keep some sky in view. We come to that later in this guide, and the answer headed Can a solid conservatory roof have roof windows goes further.
During the work, the roof is stripped in sections or under temporary cover, so the room is not left open to rain. The old sheets or glass come off first, the frame is checked in the open, and only then is the new build-up laid. That order matters, because the true state of a tired frame is often not visible until the covering is off. When something unexpected turns up, such as a rotted plate at the house wall, we show you and agree the remedy before going on.
It helps to be clear about what a solid roof is not. It will not heat the room by itself, and the room still wants proper ventilation. It improves the largest single weakness of the room, which is the roof, and leaves the walls, floor and glazing to do what they already do.
The tiled roof, layer by layer
A full tiled conservatory roof is a simplified pitched roof. Working down from the weather side, the parts are these.
- Tiles or slate. Chosen to match the house where the conservatory is visible from the street or garden. On an older house we match what is already there, so slate meets slate and stone meets stone, and a conservatory roof is matched in the same spirit.
- Battens. Small timber laths nailed across the rafters, which the tiles hang from.
- Underlay. The sheet laid beneath the battens. It carries off rain that gets past the tiles and still lets moisture out.
- Rafters. The structural timbers that span from the wall of the house to the top of the conservatory frame.
- Insulation. Fitted between and sometimes under the rafters so the roof meets the thermal standards for new work.
- Internal lining. A plasterboard ceiling that can be plastered, painted, and fitted with downlights.
Against the house wall, a flashing is cut into a mortar joint so that rain cannot track behind the roof. Flashings are strips of lead shaped over the angle where roof and wall meet. The lower edge usually carries a gutter, and any hips and valleys are finished in lead or purpose-made tile fittings. In a conservatory with an L or T plan, the inside corner of the roof is the valley, and it has to be lined and flashed with particular care. The ridge is held with mechanical fixings, since BS 5534:2014 does not rely on mortar bedding alone to keep it in place.
Because this is real roofing, it is the type with the longest published life. Third-party guides report tiled conservatory roofs lasting more than 50 years, which is longer than any sheet or glass alternative. That is a typical figure, and the real life of a roof depends on exposure and workmanship.
The lightweight warm roof
Lightweight roofs exist because many conservatory frames were built to carry glass or sheet, not a full roof. They use one of two ideas.
Insulated panels
A sandwich panel has an insulating core between two facings. One panel can reach from the wall of the house across to the frame at the front without help, without the rafters, battens and tiles of a traditional build. It goes on quickly and leaves a clean finish inside. The outside can be a tile-effect or a smooth surface, and the weight is a small fraction of a tiled roof.
Lightweight tile systems
Here a light roofing sheet pressed into the shape of tiles, or a stone-coated metal sheet, is fixed over insulation and a supporting structure. The result resembles a tiled roof from a distance, while the load on the frame is much lower than with clay or concrete tiles. The make-up is explained in the answer on what a lightweight tiled roof is.
The trade-off is in the finish and the longevity. A lightweight roof does not look or sound quite like real tiles in a close view, and its covering has a shorter record than clay or slate. For a frame that cannot be strengthened, or a modest room where a full tiled roof is not justified, it is the sensible answer. Where the frame can take it, the tiled roof wins on appearance and lifespan.
What the frame has to carry
The weight question deserves care, because it is where solid roofs most often go wrong. A glazed or polycarbonate roof was designed around its own light weight. When it is replaced by something heavier, every part below has to take more load: the frame, the walls, the foundations.
The checks run from the top down. We look at the ridge and the glazing bars or rafters and whether the frame has moved or sagged. We look at the junction with the house wall and at the head of the walls, where a ring beam is sometimes added to spread the load evenly. And we look at the walls and base, to see whether they are sound and whether anything about the foundations needs a second opinion. A tiled roof asks the most of all of these. A lightweight system asks the least.
It is not always a matter of strengthening. Sometimes the answer is to fit a lighter roof and keep the existing frame, and sometimes it is to change the frame in step with the roof. How those checks are made is the subject of the structure guide, and a quicker verdict is in the answer on tiled roof weight.
The right weight of roof is the one the frame and base can carry, and that is established on site, not from a brochure.
Light, heat and the feel of the room
People often hesitate over a solid roof because they love the brightness of the glazed one. It is a fair worry. A room with a full ceiling of plaster and tile is darker than one with a clear roof, and the answer is to plan the light rather than lose it.
Roof windows set into the slope bring daylight in from above. Whichever you choose has to meet a thermal limit. In Approved Document L, Table 4.2 lists a limit of 1.4 W/m²K where a roof window goes into an existing dwelling (a Band B window energy rating is also accepted) and 2.2 W/m²K for a rooflight. A lantern, the raised glazed feature seen on an orangery, is another option and gets its own treatment under the orangery roof guide. Large glazed doors and side windows still carry plenty of daylight, and pale ceilings and walls help it travel.
Weather inside the room is the other reward. We should explain how the survey bears on this: we note which way the conservatory faces, how much of its wall is glass and where the nearest trees and buildings throw shade, because those facts decide how much a roof change can achieve.
The reward is a steadier temperature. With a solid roof there is far less direct sun on the occupants in summer and far less heat lost through the roof in winter. It is not a substitute for ventilation, and a room that faces south with large glass doors can still run warm, so we talk through orientation with you at the survey.
Approval, listed houses and conservation areas
Putting a solid roof on a conservatory counts as material alteration work, so Building Regulations apply. You submit the application to B&NES Building Control, or you can appoint a registered building control approver. What the inspectors look at is laid out in our regulations guide.
The planning position is a separate question. For most houses it turns on the size and position of the conservatory and not on the roof covering, but a listed building or a house in the Bath conservation area raises extra questions. Conservation area status in Bath applies to around half the city. The World Heritage designation, by contrast, spreads across all of it. Things change for a listed house: the council has to give listed building consent first, and altering the roof without it is a criminal offence. Phone the council early. The planning side is covered in the answer on planning permission.
Is a solid roof right for your conservatory
The decision comes down to a handful of questions. How do you use the room? A space used daily through the year benefits most from a solid roof, while a seldom-used glasshouse may be better left as it is. What is the state of the existing roof? If only a few seals have failed, the case changes, and the repair-or-replace answer sets out how to decide. What can the frame carry, and what does your budget allow? The conservatory roof cost guide gives the typical UK ranges.
We survey the roof, photograph it, say directly which options the structure allows, and fix the price in writing once you have chosen. Ask your building control body early whether the new roof needs approval, since a solid roof adds weight the old frame was never designed to carry. The overview of conservatory roof replacement in Bath says how to start. Call 01225 285181 or send the enquiry form to arrange the survey.