How solid is each number?

Only five rows in the whole register clear the top bar, and eighty-one per cent rest on a single publisher. We say so on every page rather than presenting 222 numbers as if they were equally solid.

Band	What it means	Rows	Share
Well evidenced	Four or more sources, spread 2.0× or tighter, at least one source under 18 months old	5	2.4%
Reasonably evidenced	Two or three sources, or a spread between 2.0× and 3.0×	32	15.5%
Thin evidence	One source, or a spread above 3.0×, or every source undated	168	81.2%

Counted mechanically on 20 August 2026. Two of the five Well evidenced rows are the two that matter most commercially, the 3m × 3m and 4m × 4m tiled roof. That is not luck: the roof cluster is the one place where four independent publishers price the same job.

How a figure gets onto this site

#	Rule	Why
1	Supply only and installed are never mixed	The commonest way published conservatory prices are made to look cheap
2	Size-banded totals beat per m² rates	The rate falls about 35% from the smallest roof to the largest, so multiplying a rate by your area over-quotes small jobs
3	A typical needs two or more sourced point estimates	Otherwise the slot says so. A midpoint between two numbers we do not trust is an invention
4	Outliers get their own labelled row, never blended in	A premium national installer at 2.6× the market is real information, but it is not the average
5	Every figure carries a source name and a date	Undated sources are capped at Thin evidence automatically, however plausible they look

Contradictions we found, and what we did with them

A homeowner comparing quotes is walking into exactly these discrepancies. A site that only shows the tidy numbers is hiding the useful part.

Ref	The contradiction	Size	What we did
C2	A publisher's on-page estimator quotes £195/m² against £750/m² in its own body copy	3.8×	Excluded the estimator figure, published the reason, and do not scrape that tool
C5	Tile material-only rates published under a roof replacement label	10×	Excluded from the reconciled band
C18	Two publishers on the building control fee	2.0×	Published both bands, £200 to £800, with the likely explanation stated as a likely explanation
C19	Two publishers on structural reinforcement	3.75×	Published the full £800 to £4,000 band as conditional, and said only a survey decides which end applies
C20	The only two publishers pricing a 5m × 5m roof do not overlap at all	1.79×	Published no typical figure for that size, and said why

Every contradiction is cited to a URL and a fetch date on the page where it applies. We cite the URL rather than writing "publisher X says", because in two cases the contradiction is inside a single publisher.

What we do not know, and what would settle it

The gap	What would close it
Regional prices outside London and the South East, the North West and West Scotland	Our own submitted-quote data, which is why we store the postcode on every submission from day one, or three installer price lists per region. This is the largest gap in the register
Bay Victorian and Bay Edwardian conservatory prices	Three matched installer quotes for the same footprint. No UK source publishes either, and both are styles installers actively sell
Bespoke conservatory prices	A named architect or maker publishing a rate against a stated specification. Two specialist sites whose URLs promise a cost page contain no price figures at all

How we make money, and what we will not do to make it

When you request quotes, your details go to a lead partner who sells them to installers, and we are paid a share. That is the whole business model.

Permanently off this site

Invented installer counts. A number appears only if a covered-postcode dataset says so, with its own date
Countdown timers, survey slots running out, prices rising next month
Review counts or testimonials we did not receive
Single false-precision prices. Ranges only, rounded. Never £11,432
Pre-ticked marketing consent

What you get instead

A range, a typical, a spread, a source count and a last-checked date on every figure
Both sides of every contradiction, with the reason one is excluded
No postcode is ever rejected. If you are outside the network we tell you, and you still get the estimate
Marketing consent separate, unticked and optional
A published list of what we do not know

Sources we use, and how we grade them

Tier	Who	Weight
1	Regulators and standards: LABC, Registered Building Control Approvers, Building Regulations Parts L, K and N	Highest
2	Manufacturers publishing first-party figures: Ultraframe, SupaLite, Guardian, Eurocell Equinox	High
3	National cost publishers: Checkatrade, MyJobQuote, MyBuilder, HomeHow, whatcost, ExpertSure	Medium
4	Installer and lead-generation pages, used only where nothing better exists	Capped at thin if undated
Not a source: AI-generated summaries with no named publisher, labelled as synthesis wherever quoted		Not counted

Register last counted 20 August 2026, next full re-check due 20 November 2026. If a figure here is out of date or wrong, tell us and we will correct it and date the correction.

Now put your own numbers in

Six questions, about sixty seconds, and an estimate built from these figures with every source shown beside it.

Price my conservatory

Our Costing Method, Stated in Full