An orangery follows the same planning rules as a single-storey rear extension — usually permitted development. Here are the size limits, building regulations requirements, and costs.
No — an orangery is treated in planning terms as a single-storey rear extension and is usually permitted development, subject to the same size and location limits that apply to conservatories and extensions.
An orangery is a premium garden room with a mostly solid roof (typically a lantern light in the centre), solid dwarf walls to window height, and full thermal insulation. Despite costing considerably more than a standard conservatory, its planning position is the same: it is a single-storey rear extension under Part 1 Class A of the GPDO 2015.
This means that, within the permitted development limits, you can build an orangery without applying for planning permission, just as you would with a standard extension or conservatory.
In planning law, there is no distinction between an orangery and a conservatory — both are single-storey extensions. The difference is in construction and building regulations:
| Feature | Conservatory | Orangery |
|---|---|---|
| Roof | Mostly glazed (polycarbonate or glass) | Solid insulated roof with central lantern |
| Walls | Mostly glazed to floor | Solid dwarf walls to sill height, glazed above |
| Insulation | Limited (or exempt from building regs) | Fully insulated to extension standard |
| Building regulations | May be exempt | Always required |
| Planning position | Same as Class A extension | Same as Class A extension |
| Year-round use | Limited without extra heating | Designed for year-round use |
Because an orangery has a solid roof and is fully insulated, the building regulations conservatory exemption never applies. An orangery is always treated as a full extension for building regulations purposes.
Under Part 1 Class A GPDO 2015, an orangery is permitted development as a single-storey rear extension if:
| Rule | Limit |
|---|---|
| Rear projection (detached house) | Maximum 4m from original rear wall |
| Rear projection (semi/terraced) | Maximum 3m from original rear wall |
| Height | Maximum 4m; maximum 3m eaves height within 2m of boundary |
| Curtilage | Cannot cover more than 50% of original curtilage |
| Position | Not forward of principal elevation; not beyond side walls |
The same restrictions apply in conservation areas: a rear orangery within PD limits is permitted; a side orangery in a conservation area needs planning permission.
Unlike conservatories, orangeries always require building regulations approval. Because an orangery has a solid insulated roof and fully insulated walls, it cannot meet the conservatory exemption criteria. Building regulations cover:
A completion certificate is issued by building control on sign-off — important for future property sales and insurance purposes.
| Type | Typical Cost |
|---|---|
| uPVC/aluminium frame orangery (mid-spec) | £20,000 – £40,000 |
| Hardwood/bespoke orangery | £40,000 – £80,000 |
| Premium architect-designed orangery | £60,000 – £120,000+ |
| Building regulations application | £300 – £600 |
| Planning permission (if required) | £258 (householder) |
Orangeries cost significantly more than conservatories of similar size because of the heavier construction, solid roof structure, and higher insulation specification. However, they add more usable space and typically add more value to the property.
Extensions, loft conversions, outbuildings, solar panels — our complete guide covers everything you can build without planning permission.
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