How Much Does an Orangery Extension Cost? An Architect's UK Guide
Updated: 8 hours ago
Most orangery extensions in the UK cost between £30,000 and £80,000, at £2,500 to £5,000 per square metre excluding VAT. A small standard orangery starts at about £20,000 to £30,000, a typical mid-range project lands around £40,000 to £60,000, and premium bespoke hardwood orangeries run from £80,000 to £200,000 and beyond. Quotes for what looks like the same job can vary by a factor of three, and the sections below explain why.
Average orangery extension cost in the UK
An orangery is priced in three broad tiers, all excluding VAT:
Small standard orangery: about £20,000 to £30,000. Entry-level structures with standard glazing, basic foundations and minimal finishing. They work for some homes but don't compete on appearance, thermal performance or durability.
Typical mid-range project: about £40,000 to £60,000, with larger quality builds up to £80,000. Better glazing, hardwood or premium aluminium framing and a proper roof lantern; built to last decades.
Premium bespoke hardwood: £80,000 to £200,000 and beyond. Hardwood frames (or Accoya, a modified softwood, for painted frames), structural glazing, integrated heating and lighting, and period detailing matched to a listed house.
Orangery extension cost per square metre
In the UK, orangery extensions typically range from £2,500 to £5,000 per m², depending on materials, glazing and complexity. Standard-frame builds fall at the lower end. Hardwood and high-specification glazing push toward the upper end. Listed properties, bespoke detailing and complex sites can exceed it.
As a rough sense-check:
A 3m x 3m orangery (9 m²): £22,500 to £45,000
A 4m x 4m orangery (16 m²): £40,000 to £80,000
A 6m x 4m orangery (24 m²): £60,000 to £120,000
These ranges assume a quality build with proper foundations and finishes. Stripped-back standard builds can come in under, and premium hardwood or listed-property work can come in above.
What drives the cost of an orangery extension
Seven factors do most of the work in shaping a final orangery quote.
Size and structural complexity
Larger orangeries cost more, but not strictly in proportion to floor area. Some costs are much the same whatever the size, such as design, consents and connecting to the house, which makes a small orangery dearer per square metre. Against that, a bigger room needs a longer roof span, heavier structure and a larger lantern, which pushes the cost per square metre back up. So a 24 m² orangery typically costs roughly twice a 12 m² one, sometimes more if the larger span needs extra structure.
Frame material
The frame is one of the single biggest cost variables, and our guide to orangery materials compares them in detail.
Entry-level frames (typically plastic or basic softwood) are the cheapest option. Suitable for some homes, but they don't carry the look of a quality orangery and tend to age badly.
Aluminium sits in the middle. Slim profiles, modern appearance, strong structural performance. A reasonable choice for contemporary properties.
Hardwood is the premium option. Sapele or a similar hardwood; Accoya, a modified softwood, is an alternative for painted frames. More expensive upfront, but the look, feel and longevity are in a different category. Suits period properties especially well.
Roof design
A flat roof with a glazed lantern is the orangery's defining architectural feature. The size of the lantern, the quality of the glazing in it, and the proportions of the surrounding flat roof all affect cost. A full glass roof costs more again and demands a high thermal spec to be usable through winter. Our guide to orangery roof lanterns covers how lantern size and glazing are chosen.
Glazing specification
Standard double glazing is the baseline. Most quality orangeries now use upgraded double or triple glazing with low-emissivity coatings and inert gas filling. Solar-control glass, self-cleaning glass and acoustic glass are common upgrades, each adding to the cost but improving comfort and reducing running costs.
Site conditions and groundworks
What happens below ground level catches people out. Poor ground conditions, high water tables, awkward access, drainage runs or services that need diverting can all add tens of thousands to a project before the first frame is delivered. A proper site survey before quoting is essential.
Internal finishes and fit-out
The orangery shell is one cost. The fit-out is another. Underfloor heating, premium flooring (stone, hardwood, polished concrete), bespoke cabinetry, lighting design, plastering and decoration can comfortably add £15,000 to £40,000 on top of the structural cost. Some of this depends on how the orangery is used: a kitchen orangery costs significantly more than a sitting-room orangery once cabinetry and appliances are factored in.
Planning, design and consents
For projects requiring full planning permission, Listed Building Consent or a Larger Home Extension prior approval, the design and consents stage adds professional fees and time. Architectural drawings, planning applications, structural engineering and building control fees together typically run to several thousand pounds.
Lean-to orangeries: a lower-cost option
Not every orangery needs to be a full standalone structure. A lean to orangery extension shares one wall with the existing house and uses a sloping roof rather than a flat roof with a lantern. The build is simpler, the structural demands are lower, and the cost typically comes in below an equivalent-sized full orangery.
It suits a home where the budget doesn't stretch to a full orangery but a light-filled room that performs better than a basic conservatory is still the aim.
Orangery vs conservatory: which costs more?
An orangery generally costs more than a conservatory of the same footprint; our guide to conservatory cost gives the conservatory side of the comparison, and our orangery vs conservatory guide sets out the design differences. The extra cost comes from the brick or stone piers between the glazed sections, the flat roof with lantern (rather than a fully glazed pitched roof), and the higher thermal specifications that orangeries usually carry.
The trade-off is that orangeries tend to feel more like a permanent part of the house, perform better year-round, and add more value at resale. A conservatory can feel like a glazed lean-to in winter. An orangery, designed properly, doesn't.
Orangery vs traditional extension cost
A standard brick-built single-storey extension can sometimes cost less than an orangery of the same size, particularly at the budget end of the market. At the premium end, the comparison narrows: a high-specification extension with quality glazing, roof lights and finishes can match or exceed an orangery of equivalent size.
What you get is different. An extension prioritises wall space, privacy and storage. An orangery prioritises light, garden connection and architectural feature. Which is right depends on how you want the new space to feel, not just what it costs.
Hidden costs and extras to budget for
A few costs aren't always visible in the headline quote.
VAT. The figures in this guide exclude VAT, which is charged at 20%. On a £60,000 project that is £12,000, so check whether each quote you receive includes it.
Building regulations fees. Application and inspection fees are modest but real.
Connecting services. Extending heating, electrics and drainage from the existing house adds cost, especially if the supply needs upgrading.
Decoration and finishing. Some quotes stop at plastering, leaving the homeowner to decorate. Confirm what's included.
Landscaping reinstatement. Building works disrupt gardens. Restoring paths, planting and lawns is usually outside the build contract.
A 10 to 15% contingency on top of the build cost is sensible. Even well-planned projects produce one or two surprises during construction. Set the budget before the brief, and compare itemised quotes from at least two specialists: the cheaper headline often leaves out foundations, glazing upgrades, finishing, building control fees or VAT.
Does an orangery extension add value to your home?
A well-designed, well-built orangery typically adds value at resale, though the figure depends on the local market and the quality of the build. Orangeries tend to add more than equivalent-sized conservatories, particularly on period properties where the design matches the house. A budget standard structure rarely adds value; a quality hardwood orangery extension on a well-proportioned house often more than recovers its cost.
How to estimate your orangery cost
A quick way to build a working budget, using the figures in this guide:
Floor area x £2,500 to £5,000 per m². Use the lower end for a simple standard-frame build and the upper end for bespoke hardwood, a large lantern or a listed house.
Add fit-out. Heating, flooring, lighting and finishes typically add £15,000 to £40,000; an orangery kitchen typically starts from about £25,000, and a larger fully fitted one can exceed £60,000.
Add fees and consents. Drawings, structural engineering, planning and building control.
Add VAT at 20%.
Add a 10 to 15% contingency.
A 4m x 4m hardwood orangery at the upper end, with a mid-range fit-out, is therefore a very different budget from the same footprint in a standard frame, which is why a site visit comes before a firm price.
Orangery cost questions, answered
Is an orangery cheaper than an extension?
Not usually at the budget end, where a basic brick extension can cost less. At the premium end the two converge, and a high-specification orangery and a high-specification extension of the same size cost much the same.
How long does an orangery take to build?
It depends on the planning route more than the build. A project under permitted development moves from design to site faster than one needing planning permission or listed building consent, and the frames are made to order after the survey, so the timeline is set at design stage.
Does an orangery need planning permission?
Often not, if it fits within permitted development, but it depends on size, position and the house. Our guide on whether you need planning permission for an orangery covers the rules.
Talk to our design team
If you are planning an orangery and want a sense of what yours might cost, get in touch with the studio.
