Orangery Costs UK 2026 — How Much It Costs to Build an Orangery by Size

What Is an Orangery and Why It Costs More Than a Conservatory

The distinction matters because it drives the price. A conservatory is a lightweight glazed structure: a dwarf wall, full-height glazing, and a glass or polycarbonate pitched roof. An orangery keeps the bright, garden-room feel but is far more substantial — solid masonry piers between the windows, a flat insulated perimeter roof topped with a parapet, and a glazed roof lantern set into the centre of the flat roof. That extra masonry and roof structure means deeper foundations, more brickwork, more skilled trades on site and, in most cases, full building regulations approval.

Because an orangery has more solid wall and a properly insulated flat roof, it holds heat far better than a conservatory and is usable year-round. It is also noticeably cheaper than a full brick single-storey extension, because the roof lantern and large glazed openings replace the cost of a fully tiled roof and solid walls. That positioning — warmer than a conservatory, cheaper than an extension — is the core of the sales pitch and the reason demand is strong.

Orangery Costs by Size

The single biggest driver of total cost is floor area, but the specification — lantern material, glazing type, heating and internal finish — moves the final figure significantly within each band. The ranges below are realistic UK supply-and-fit figures for 2026, including foundations, masonry, roof, glazing and a standard internal finish.

Small Orangery (around 3x3m / 9m²)

A compact orangery suited to a kitchen-diner extension or a snug garden room. At this size the fixed costs — foundations, scaffolding, a roof lantern, building control — make up a larger share of the total, so the cost per m² is higher than a larger build.

• Typical total cost: £20,000–£30,000
• Cost per m²: £2,200–£3,300/m²

Medium Orangery (around 4x4m / 16m²)

The most common size ordered, large enough for a dining area or a generous living space while staying comfortably within permitted development for most homes. The fixed costs are spread across more floor area, so the per-m² rate settles into the middle of the range.

• Typical total cost: £30,000–£45,000
• Cost per m²: £1,900–£2,800/m²

Large Orangery (around 5x5m+ / 25m²+)

A large orangery becomes a major room — open-plan kitchen extensions, large family living spaces. At this scale a larger or second roof lantern, bi-fold doors and underfloor heating are common, pushing the upper end well past £70,000 on a high specification.

• Typical total cost: £45,000–£70,000+
• Cost per m²: £1,800–£2,800/m²

Note how the cost per m² falls as size increases — the fixed costs of foundations, access and building control are diluted across more floor area. This is worth explaining to customers who compare a small and large quote and assume the bigger one is poor value; on a per-m² basis it is usually the better deal.

What Drives the Price — Cost Elements Explained

An orangery is a multi-trade build, and each element carries its own cost. Understanding the breakdown helps you quote accurately and explain to customers why the figure is what it is.

Foundations and Groundworks

Because an orangery carries solid masonry piers and a flat roof, it needs proper strip or trench-fill foundations dug to building-control depth — typically deeper and more substantial than a conservatory's lightweight base. Ground conditions are the big variable: nearby trees, made-up ground, a high water table or proximity to drains can force deeper digs, engineered foundations or a drain build-over agreement, each adding cost. Allow £4,000–£9,000 for groundworks and the base slab on a typical build, more on difficult sites.

Brick and Blockwork Piers

The solid masonry piers between the glazed openings are what define an orangery. They are typically built as an insulated cavity wall — outer brick to match the house, blockwork inner leaf, insulation between — and finished with a parapet at roof level. Matching reclaimed or specific facing bricks to an older property adds cost and lead time. Budget £5,000–£12,000 for masonry depending on size, the number of piers and brick matching.

The Roof Lantern

The glazed roof lantern is the signature feature and one of the largest single line items. Aluminium lanterns (Atlas, Korniche, Ultraframe and similar) are the most common — slim sightlines, low maintenance, strong thermal performance — while timber lanterns suit heritage and high-end projects at a premium. Size and the number of lanterns drive the cost: a single lantern on a medium orangery runs £2,500–£6,000 supplied, with large or multiple lanterns and timber options pushing well above that. The surrounding flat roof itself — a warm, insulated flat roof finished in EPDM, GRP or felt with a parapet — adds further cost.

Glazing, Bi-fold and French Doors

The vertical glazing between piers — and the doors out to the garden — is a major spend. Standard French doors are the budget option; aluminium bi-fold or sliding doors are the popular upgrade and cost considerably more. Expect £1,200–£2,500 for a quality set of French doors and £2,500–£6,000+ for aluminium bi-folds, depending on width and spec. All glazing should be A-rated double or triple glazing to meet building regs.

Internal Finishing — Plastering, Electrics and Heating

Unlike a conservatory, an orangery is finished like a proper room: plastered walls and a plastered perimeter ceiling soffit around the lantern, skirting, painting and flooring. Electrics — sockets, lighting, sometimes a feature pelmet around the lantern — must be certified to Part P. Heating is usually either radiators tied into the existing system or, increasingly, wet underfloor heating, which suits the large glazed space well. Budget £3,000–£7,000 for plastering, electrics, decoration and flooring, plus £1,500–£4,000 if underfloor heating is specified.

Building Regulations and Planning

This is a key difference from conservatories and a common source of confusion in quoting. Many conservatories are exempt from building regulations because they are separated from the house by external-quality doors and are under 30m². Orangeries usually are not exempt — the solid roof, the level of glazing relative to floor area, and the way they are typically opened up to the main house mean most orangeries require full building regulations approval. Any build over 30m², or any work that removes a structural wall to open the orangery into the house (requiring a steel beam), will need building control sign-off regardless.

Building control fees and structural engineer's calculations for a steel beam add cost — typically £500–£1,500 combined — and should always be a separate line in your quote rather than buried in the price.

On planning, most orangeries fall under permitted development and do not need a full planning application, provided they stay within the limits: single-storey rear extension depth (up to 3m for an attached house, 4m for a detached, subject to the larger home extension rules), height limits, and not covering more than half the garden. Listed buildings, conservation areas, and homes where permitted development rights have been removed are the exceptions — these need planning permission. Always confirm the customer's situation before quoting; a Lawful Development Certificate is worth recommending for peace of mind.

How an Orangery Compares on Price

Customers almost always weigh an orangery against the two things either side of it. Being able to frame the comparison clearly helps you close the job.

• Versus a conservatory: an orangery typically costs 40–80% more than a comparable conservatory. A mid-range conservatory of similar size might be £12,000–£20,000 against £30,000–£45,000 for the orangery. The buyer is paying for solid walls, a warm flat roof, building-regs compliance and year-round usability.
• Versus a full single-storey extension: an orangery is usually cheaper than a fully brick-built, tiled-roof extension of the same footprint — often by 15–30% — because the lantern and large glazed openings replace expensive solid roof and wall construction. A full extension of comparable size might run £45,000–£75,000+ where an orangery lands lower.

That middle-ground position — warmer and more permanent than a conservatory, lighter and cheaper than an extension — is the entire reason orangeries sell. Lead with it.

Finishing Costs Customers Forget

The structural build is only part of the spend, and quotes that ignore the finishing extras leave the customer with an unwelcome surprise. Flag these clearly:

• Flooring: tiling, engineered wood or LVT across a 16m² room adds £800–£2,500 once supplied and laid.
• Blinds for the lantern and glazing: made-to-measure lantern blinds are expensive — £1,000–£3,000 is common for a full set.
• Knocking through to the house: removing the original external wall, fitting a steel beam, making good and replastering can add £2,000–£5,000.
• Decoration and furniture: not your line, but worth setting the customer's expectation that the room still needs finishing once you hand over.

Quoting Tips — What to Check Before You Price

Orangery quotes go wrong when groundworks and building control are underestimated. Before you commit a price, check the following:

• Ground conditions: trees, made-up ground, sloping sites and drain runs all affect foundation depth and cost. Dig a trial hole if you are unsure.
• Drains: if you are building over or within 3m of a public sewer, you need a build-over agreement from the water authority — factor in time and cost.
• Brick matching: matching the existing house brick can mean sourcing reclaimed or specials at a premium and a longer lead time.
• Knock-through structure: if the orangery opens into the house, price the steel beam, engineer's calcs and making good as separate items.
• Lantern size and number: confirm the lantern specification early — it is one of the biggest single costs and easy to underquote.
• Planning status: check for conservation area, listed status or removed permitted development rights before assuming no application is needed.

Quick Reference: Orangery Costs UK 2026

Quick Reference: Cost Element Breakdown