From Conservatory to Orangery: What Changes
Two things have to change for a conservatory to read as an orangery: the roof has to become mostly solid with a glazed lantern in it, and the walls have to become masonry piers with glazing between them. The first is a well-priced job. The second is not priced by anybody in the UK as a retrofit, and this page says so rather than interpolating. If you want the two products compared instead of converted, start at orangery against conservatory cost.
The half of the job that is priced · solid roof on an existing 3m × 3m conservatory · installed inc VAT
£6,000 to £11,000 plus masonry nobody prices
Well evidencedFour UK publishers within 1.05x on the floor, typical £8,075. Building control adds £200 to £800, Reasonably evidenced but conflicted. No UK source prices the piers, or the conversion as a job. A new orangery is £30,000 at 16 m². Checked 20 August 2026.
How much does it cost to convert a conservatory to an orangery?
Nobody publishes a figure. Our register holds 222 price rows drawn from every mainstream UK cost publisher and not one prices this conversion as a job. What follows is assembled from the component rows that do exist, each with its own source and grade, and the components that do not exist are left empty.
| Component | Low | High | Evidence | Sources |
|---|---|---|---|---|
| Solid roof, 3m × 3m (9 m²) | £6,000 | £11,000 | Well | Four UK cost publishers |
| Solid roof, 4m × 4m (16 m²) | £8,000 | £14,400 | Well | Four UK cost publishers |
| Building control approval | £200 | £800 | Reasonably, conflicted | Two UK cost publishers, 2026 and Mar 2026 |
| Structural reinforcement, if the frames need it | £800 | £4,000 | Reasonably, conflicted | Two UK cost publishers, May 2026 and 2026 |
| Structural engineer's report | £300 | £500 | Thin | Google AI Overview synthesis, publisher not attributed |
| Masonry piers and their foundations | no figure | no figure | Gap | No UK source prices them as a retrofit |
| The conversion as a single job | no figure | no figure | Gap | No UK source prices it |
Checked 20 August 2026. Do not read the rows as a total: adding the priced ones together gives you a solid roof with paperwork, not an orangery conversion. The engineer's report line is a figure Google's own AI Overview synthesises from the ranking pages without attributing it, which is why it is capped at Thin evidence and labelled as synthesised.
What actually changes
Three things, and only the first is a roofing job.
The roof stops being glazing and becomes structure. An orangery roof is mostly flat and insulated with a glazed lantern set into it, rather than a pitched glazed roof with bars. Insulated roof systems publish 0.10 to 0.18 W/m²K against 0.83 to 3.2 for polycarbonate, which is the whole reason people do this. Manufacturer technical literature, verified 20 August 2026.
The walls stop being frames and become masonry. Piers or columns replace window frames at the corners and often between bays, and they need foundations that a conservatory dwarf wall may not have. This is the part that turns a roofing job into a building job, and the part with no published price.
The exemption goes. A conservatory can sit outside the Building Regulations under Schedule 2 Class 7 while it stays glazed to a significant proportion and thermally separated. Put a mostly solid roof and masonry walls on it and it is very unlikely to still qualify, so the work becomes a material alteration and the new roof has to reach 0.15 W/m²K in England. Approved Document L Volume 1 2021, Table 4.2, verified 20 August 2026.
Who signs it off matters more than who quotes it. Regulated work here goes to Local Authority Building Control or a Registered Building Control Approver. No competent person scheme covers it. FENSA states that conservatories fall outside its scheme, and the CERTASS competent person scheme lists conservatories under what cannot be registered. Verified 20 August 2026.
The roof half of the job
This half is the best-evidenced figure anywhere in our register. A tiled or solid replacement roof is £6,000 to £11,000 at 3m by 3m, typically £8,075, and £8,000 to £14,400 at 4m by 4m, typically £10,700. Well evidenced in both bands, four independent publishers landing within 1.05 times on the small floor and 1.20 times at both ends of the larger row, their tables dated 2026, July 2026, December 2024 and undated. Both typicals are the median of the sourced point estimates rather than the midpoint of the band, because the distribution is right-skewed and a midpoint would be an invention. Checked 20 August 2026.
Those rows include removal and disposal of the existing roof, the new insulated system, structural fixings, a plastered or boarded internal finish and guttering where it is replaced. They exclude scaffolding, building control, structural reinforcement, roof windows and electrics. The decision itself, size band by size band, is at solid roof conservatory cost, and the whole-job view across every covering is at how much it costs to replace a conservatory roof.
One conditional cost sits behind all of it. A lightweight solid roof adds roughly 0.5 kN/m, which LABC describes as less than 10 per cent over a typical translucent roof, so foundations are rarely the problem. The real question is whether your mullions contain steel, which is invisible from outside and settled only by a magnet test or pilot holes. If they do not, reinforcement runs £800 to £4,000, Reasonably evidenced but conflicted: one publisher (May 2026) prices reinforcing existing frames at £800 to £2,500, a second (2026) prices replacing them at £3,000 to £4,000. We attach no probability to either, because nobody publishes one. Checked 20 August 2026.
The brickwork half, and the row we will not reuse
Here the honest answer is a gap. No UK cost publisher prices building masonry piers into an existing conservatory, and that includes all four of the major UK trades directories and quote sites in our register. The nearest thing we hold is a removal line, worth naming precisely so that nobody, including us, presses it into service.
The only row in our register that names brick piers prices taking them down. Removal of an orangery with brick piers at 5m by 4m is £1,770 to £2,450, Thin evidence, one publisher, squote.app, 26 June 2026, checked 20 August 2026. That is a demolition figure. Quoting it as the cost of building piers would be the same class of error as pricing a roof from a skip-hire line, so we publish it only as the thing we are refusing to reuse.
There is a second absence behind it. No UK cost site has a conservatory base guide at all: one national trades directory's own base cost URL returns a 404, and the other three major publishers have no equivalent, so every base figure in our register had to be extracted from inside a general guide. Base and groundwork is typically £2,000 to £4,000 of a new conservatory quote, Thin evidence throughout, checked 20 August 2026, and the rows we could extract are at conservatory base and groundwork cost.
So the brickwork half will be priced by a builder against your own house rather than against a table, and the quotes will vary more than the roof quotes do. Ask for the piers, the foundations under them and the making good to be itemised separately from the roof: separate trades, separate risks.
Frames and columns
The frames you keep matter as much as the masonry you add, because glazing between piers still sits in a frame. SAP gives aluminium a whole-window U-value of 2.1 against 1.7 for uPVC and timber, and aluminium needs a thermal break to reach that. SAP 10.2 Table 6e, verified 20 August 2026. That is the opposite of what aluminium is usually sold on, and worth knowing before you specify slimmer sightlines between the piers. What each material costs is at uPVC, aluminium and timber frame prices .
Where the money goes, and where it does not
We hold one real itemised orangery in the whole dataset. It is a new build rather than a conversion, but its shape is the most useful guide available to where the money goes. A 4m by 3m orangery in Waterlooville came to £33,644 including VAT, Reasonably evidenced as an itemised project, Precision Extensions, 12 January 2026, checked 20 August 2026: base and walls £9,689, frames and roof £11,934, installation £4,235, electrics, heating and finishes £5,576, fees £2,100, structural work £110.
Read it as a proportion. Base and walls are 29 per cent of a new build, and a conversion does not avoid all of that: you keep the slab and probably the dwarf wall, but the piers and their foundations are new work. Fees are 6 per cent, which is consistent with the £200 to £800 building control band above.
If you want the same arithmetic applied to your own roof rather than to somebody else's orangery, work out what your roof will cost first, then have local installers price it alongside the masonry.
Buying a new one instead
At some point converting stops being cheaper than starting again. A new orangery at 16 m² is £30,000 to £35,000, typically £32,500, Reasonably evidenced across three sources anchored on a national trades directory's orangery guide, March 2026. All in, the reconciled mid-market rate is £2,000 to £2,500 per m², Reasonably evidenced after reconciling four publishers whose raw rates span 6.4 times. Checked 20 August 2026.
Against that, the priced half of a conversion is £6,000 to £11,000 of roof plus £200 to £800 of fees, both checked 20 August 2026, and an unpriced masonry half. The test is arithmetic on your own quotes rather than a threshold we could publish: add the builder's masonry line to the roof line, and once the total approaches what a new orangery costs at the same footprint you are comparing against a new structure with a new base and a fresh warranty rather than against your existing frames.
Price the half we can price
Six questions, about sixty seconds, and an estimate built from the rows above with every source shown.
We price conservatory roofs properly and we will not pretend to price masonry piers we have no source for. Get the roof half costed from published rows in the Conservatory Cost Calculator, then get quotes from local roof installers and have the builder price the brickwork as a separate line.
Check what your roof will cost
We are paid when an installer quotes you. That is the whole business model, and it is why the masonry line on this page says “no figure” instead of carrying a number we could not defend.
Or just a usable room
A lot of people asking about this conversion do not want an orangery. They want a room they can sit in during February, and the word arrived with the quote. If that is you, the masonry half is optional and the roof half is the whole job, which changes the budget by tens of thousands. The legal consequences and the fees are at turning a conservatory into a room you can use.
Questions people ask first
Can you actually convert a conservatory into an orangery?
Why will you not give me a total for the whole job?
Will it need building regulations approval?
Is converting cheaper than building a new orangery?
Do the piers have to go on new foundations?
Every figure on this page was last checked 20 August 2026, next check due 20 November 2026. Two components on this page carry no figure at all, and that is the finding rather than an omission: a conservatory to orangery conversion has never been priced as a job by a UK publisher we could cite.
Find out what yours costs
Six questions, about sixty seconds, and an estimate built from published UK figures with every source shown. Then up to four local installers can quote you, if you want them to.