How Much Does an Orangery Extension Cost in 2026? (UK)
A typical orangery extension costs £30,000–£75,000+ in 2026. The biggest drivers are floor area, the lantern roof, glazing specification and how much groundwork your plot needs. Here is the full price breakdown, what pushes costs up or down, and how to compare builder quotes properly.
Orangery extension cost breakdown 2026
For a quality orangery extension in 2026 you should budget £2,500–£3,500 per m² for a standard build, rising to £4,000+ per m² for premium glazing, structural openings and high-end interior finishes. A small 12 m² orangery lands around £30,000–£40,000, a typical 20 m² build £45,000–£60,000, and a large 30 m²+ orangery with bi-fold doors and underfloor heating can exceed £75,000.
What drives the price up
The lantern roof is the defining feature of an orangery and a major cost — a large or bespoke lantern adds several thousand pounds over a flat or tiled roof. Glazing spec (double vs triple, solar control, bi-fold or sliding doors), groundworks (foundations, drainage diversions, a sloping plot) and internal finishes (underfloor heating, plastered ceilings, kitchen integration) are the other big levers.
Orangery vs conservatory cost
An orangery costs more than a conservatory of the same size because of its solid pillars, parapet roof and lantern. Expect to pay roughly 20–40% more than an equivalent conservatory, but you gain a more substantial, year-round room that reads as a true extension rather than a glazed add-on.
How to budget and compare quotes
1. Set the floor area
Fix the internal footprint in m² first — it is the single biggest driver of the final figure.
2. Choose the roof and glazing
Decide on lantern size, glazing spec and door type before you ask for quotes so every builder prices the same thing.
3. Allow for groundworks
Difficult access, drain runs and a level base can add £3,000–£8,000 — make sure quotes include them.
4. Get three like-for-like quotes
Compare quotes on identical spec so you are judging build quality and service, not just headline price.
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