Not every conservatory owner wants to lose the sky. A solid tiled roof gives a room that lives like part of the house, but it also closes in the space that made the conservatory worth having. Glass is the alternative, and it has moved on a long way from the single clear panes that made older conservatories too hot in summer and too cold in winter. Modern glazing carries coatings on the inner surfaces that deal with heat in both directions, and it sits in frames designed to hold it. This guide looks at that option as a replacement for a tired polycarbonate or older glass roof. It sets out what solar-control glass does, how it compares for life and weight with the other coverings, what the structure needs to carry it, and where glass is the wrong choice. We do not push one answer. We tell you which suits your room once we have looked at it.
What solar-control glass actually does
Ordinary glass lets almost all the sun's energy straight into a room, and then lets the room's warmth leak out again at night. A conservatory with clear glazing on every face therefore swings between hot afternoons and cold evenings. Solar-control glass tackles the first half of that. A thin coating, invisible from inside, is applied to one of the surfaces of the sealed unit. It reflects part of the sun's heat back outward before it can build up in the room, while still passing a good share of daylight. The result is a glass roof that stays brighter than a solid one and avoids the greenhouse effect of an older clear roof.
The second half is heat loss. A sealed double-glazed unit has two panes with a gap between them, and that gap is usually filled with a gas that conducts heat more slowly than air does. A low-emissivity coating on the inner pane helps to hold the room's warmth in. Many modern conservatory roof units combine both coatings, so they cut summer glare and slow winter heat loss in the same piece of glass.
The outer pane is often toughened or given a self-cleaning surface, and the inner pane is laminated. Laminated glass is two sheets joined by a tough interlayer, which holds the pieces together if the glass cracks. That matters overhead, because broken glass should stay in the frame instead of falling into the room.
None of this makes glass the same as insulation. A glass roof, however well coated, is not a solid, insulated structure, and the room under it will still feel the weather more than the rest of your house. Blinds, ventilation and sensible heating cover that gap, and our guides on a cold conservatory and on a conservatory that gets too hot go into the practical side.
Glass, polycarbonate and solid compared
The three main coverings differ most in how long they last, how much they weigh and how the room feels. Lifespans below come from two published sources, and both vary with exposure, installation and care, and neither is a promise.
| Covering | Typical life | Source |
|---|---|---|
| Polycarbonate | About 10 years, or 10 to 15 years | HomeBuilding (2024); The Eco Experts (2024) |
| Glass | In excess of 30 years | HomeBuilding (2024) |
| Tiled solid roof | In excess of 50 years | HomeBuilding (2024) |
On those figures, glass lasts roughly three times as long as polycarbonate. That does not make it the automatic winner, because the glass will outlive the seals around it only if the frame stays sound and watertight. The sealed units can fail separately: misting between the panes means the seal has gone and the unit needs replacing, even if the frame is fine.
Weight separates them too. Polycarbonate is light. Glass is considerably heavier, though still lighter than a tiled roof with its timber, insulation and ceiling. That puts glass in a middle position, which is exactly why it suits a frame that cannot be strengthened to take tiles. Our guide on how a frame, walls and footings are checked explains how the frame is assessed, and the same checks apply here, only at a lower load.
Feel is the last difference. A solid roof gives a room that matches the rest of the house in warmth and sound. Glass keeps the light and the view of the sky, with the compromises above. Which matters more is a question about how you use the room, and we ask it at the survey.
What the frame and walls must carry
Glass is heavier than sheet plastic, so a swap from polycarbonate to glass is not a like-for-like change in the load. The roof bars have to be strong enough, and they have to hold the glazing units in place without flexing. A frame that carried polycarbonate for years may have been fine for its time, but a glass unit is a different proposition.
In practice the frame is judged by what is in it. Aluminium roof bars designed for glazing carry the units with a seal on either side, and new glass roofs are normally supplied as a system with their own bars. If you keep the existing frame, we check the eaves beam, the corner posts and the ridge, and we confirm that the walls underneath are sound and level. A twisted or sagging frame will not seat sealed units properly, and the gaps that result let water through.
Many owners take the chance to replace the roof bars together with the glass, even when the frame below is kept. New bars come with new gaskets and cappings, and they remove the risk of fitting a good unit into a worn channel. It adds to the price and takes out a common cause of later leaks.
A glass roof is a replacement of the covering and its bars. The frame, the dwarf walls and the footings still need to be sound, and we record their condition in the survey before a figure goes in the quote.
Where a solid roof requires a Building Regulations application, a glass roof raises a different question that building control answers case by case. Because the position depends on the design, ask building control before you order, and tell us what the answer is, so the paperwork matches the work. A planning or consent angle can also apply on a listed house or in a conservation area, which we cover in our guide to listed building and conservation settings.
Where glass wins, and where it does not
Glass is a strong choice in some situations and a weak one in others. These are the ones we see most often.
Where glass suits
- A room used as a dining space or sitting room in daylight. The light is the whole point, and a solid roof removes it.
- A frame that cannot take extra weight. Glass sits between polycarbonate and tiles, so it can fit where tiles would need strengthening.
- A south-facing garden room with shade nearby. Solar-control coatings, blinds and a tree or two can keep summer heat within reason.
- A view worth keeping. Many Bath gardens slope or look over trees, and glass keeps that connection.
Where it struggles
- A room you want to use all year as a proper extension. A solid insulated roof keeps temperature steadier, and a glass roof, even a good one, cannot match it.
- A room that faces strong afternoon sun with no shade. Even coated glass lets in heat, and you may end up relying on blinds and ventilation.
- A room used for a home office or a bedroom. Glare, noise from rain and temperature swings all make these uses harder.
Noise is worth a line of its own. Rain on glass is quieter than rain on polycarbonate, but louder than on a tiled roof with an insulated ceiling. If the room doubles as a place to work or to sleep, that may tip the choice.
Maintenance differs as well. Glass needs washing, and it shows moss and algae where trees overhang. Solid roofs need little beyond clearing gutters and checking flashings. We would rather you picked the covering you will enjoy and maintain than the one that sounds best on paper.
Cost and what moves it
The price figures for glass roofs are less well documented than for tiled or polycarbonate roofs, and we do not invent a separate number for it. What we can quote is the published range for conservatory roof replacement in general. MyBuilder's conservatory roof cost guide (2026) reports typical UK prices of £2,000 to £10,000 or more, averaging about £4,500, with roof type, size and shape, frame and foundation upgrades and Building Regulations among the factors. These are national ranges and say nothing about our own pricing. The figure we put in writing comes after the survey.
Several things move a glass roof price within that wide spread. Roof size and shape come first: a simple lean-to is far less complicated than a Victorian or P-shaped roof with hips, valleys and a ridge, which means more cut glass, more bars and more joints to seal. The specification of the glass is next. A plain double-glazed unit costs less than a unit with solar-control and low-emissivity coatings, laminated inner pane and a self-cleaning outer face. The condition of the frame follows, and whether the bars are replaced or kept.
Access and scaffold matter on a taller or awkward conservatory. Lifting large sealed units into place on a restricted site, as in many terraced Bath gardens, may need more people or equipment than a simple roof does. We look at the route in and the working space at the survey, and the quote names them.
The ongoing cost is part of the choice as well. A glass roof is cheaper to heat than a polycarbonate one that leaks warmth, and dearer than a fully insulated solid roof, which holds temperature best. The cost of blinds, ventilation and cleaning also belongs in the sum. Our page on conservatory roof options sets the three side by side.
How we help you decide
The sensible way to choose is to start with how you use the room, then check the structure, and let the price follow. We come to look at your own roof and take photographs of what is there. Then we talk through the options, one at a time, with the cost and the compromises of each.
If you want daylight and the frame is sound, glass is a good answer and we will price it. If you want a room that works as part of the house in every season, we will say a solid roof is the better fit, and what the frame needs to carry it. If the old roof is only leaking at one joint, we will say so, since a repair could be the whole job. We repair where repair works.
Matching the design to the house matters too. On a period property, the roof bars, the colour and the profile need to sit comfortably against the existing windows and stonework. A listed house or a house in the conservation area brings other considerations, and a quiet conversation with B&NES planning before work begins avoids trouble later. Bath is a World Heritage Site throughout, and about half of it lies within the conservation area, so asking is sensible even for a modest change.
When you accept a quote, it is priced in writing and fixed, with the structure, the glass specification, the bars and the finishing described line by line. Waste leaves with us, the site is left clear, and our own workmanship carries the 10-year written guarantee. The glass units carry the manufacturer's own warranty, which is separate. Ring 01225 285181, send a WhatsApp or fill in the form on the conservatory roof replacement page.