Solid conservatory roof costs area times the installed allowance plus confirmed extras and tax; the default example is about £10,800.
Measure the plan of the conservatory
Conservatory installers usually discuss a replacement system against the room's roof plan. This calculator follows that basis, rather than applying the slope multiplier used for a house roof. Enter the external width and projection. A lean-to, Edwardian rectangle or gable-fronted rectangle uses width times projection. For a Victorian frontage, two equal right-triangle corner cuts are deducted. A P-shape adds a second adjoining rectangle; enter only the wing outside the first rectangle so the junction is not counted twice.
These simple plans describe an area, not a structural design. An irregular bay, curved frontage or unusually complicated valley needs an installer measurement. The existing polycarbonate or glass selection identifies the removal scope to discuss. It does not automatically apply a demolition premium. Standard removal is normally part of a replacement package, so add another removal allowance only if your actual quote excludes it.
Example: a 4 m by 4 m solid roof
Sixteen square metres of lightweight tiled solid roof uses a before-VAT range of £375 / £562.50 / £750 per m². At the typical allowance, 16 × £562.50 = £9,000. VAT at 20% adds £1,800. The total and rounded headline both show £10,800. Internal plastering, a pelmet, electrics and frame reinforcement are set to zero in this example and are excluded unless a confirmed extra quote is entered.
Glass, polycarbonate or lightweight tiles?
| Replacement system | Checkatrade published installed GBP/m² | MyJobQuote published installed GBP/m² |
|---|---|---|
| Polycarbonate | £400–800 | £175–350 |
| Glass | £600–1,200 | £200–400 |
| Solid / tiled | £600–900 | £300–600 |
Read 1 October 2026: Checkatrade conservatory roofs and MyJobQuote replacement roofs. These guides describe very different quote ranges. Their tax treatment is not stated consistently; the net envelope permits inclusive and exclusive interpretations, then blends the endpoints. Its midpoint is a planning figure, not a claim that every replacement costs that amount.
Glass keeps overhead light, but the glazing specification and solar control can change the quote. Polycarbonate is a like-for-like panel choice. A solid system changes weight, daylight and thermal performance. Ask for the manufacturer's system name and confirmation that the existing frames and foundations can support it. Do not assume a lightweight tiled roof can simply be fitted onto any old glazed structure.
Building control and the ceiling finish
Planning Portal's conservatory roof guidance says a new roof must address structural safety, energy efficiency and ventilation. This guidance relates to England; Scotland, Wales and Northern Ireland need their own checks. Discuss a solid-roof conversion with building control before ordering. An existing conservatory exemption does not establish that an altered structure still meets the relevant conditions.
Clarify who will plaster and paint the ceiling, whether spotlights require new electrical work, and whether a pelmet or internal trim is included. Those are separate homeowner quotes here. A low external-roof price can become a much larger finished-room budget once these trades are added.
Compare the appropriate roof tools
An adjoining extension may need the flat roof replacement cost calculator UK. The main house covering belongs in the UK roof replacement cost calculator, while an outbuilding belongs in the garage roof replacement cost calculator UK. Use the roof pitch calculator to discuss angles with the system supplier.