A garden room is an outbuilding in the rear garden used as an office, studio or gym. It sits under Class E of the GPDO and is one of London's fastest-growing extension types post-pandemic.
Outbuildings including garden rooms are permitted development under GPDO Schedule 2, Part 1, Class E, provided they are incidental to the enjoyment of the house.
London is different. Conservation area coverage, Article 4 directions and listed buildings are much more common in London than the national average, and any of them can remove the PD route. Use the address-level checker before you assume PD applies.
These are the national permitted development limits set by Schedule 2 of the GPDO. If your scheme stays within every rule and no local constraint removes PD, you will not need planning permission — but you may still want a Lawful Development Certificate to prove it.
| # | Rule |
|---|---|
| 1 | Maximum height 2.5m if within 2m of any boundary. |
| 2 | Maximum eaves height 2.5m and overall height 4m (dual-pitched roof) or 3m (any other roof). |
| 3 | Must not be forward of the principal elevation fronting a highway. |
| 4 | Total footprint of all outbuildings cannot exceed 50% of the original curtilage. |
| 5 | Must be single-storey. |
| 6 | Use must be incidental to the dwelling — not primary residential accommodation. |
| 7 | Verandas, balconies and raised platforms are not allowed. |
These are the common reasons a garden room loses the permitted development route in London and needs a full householder application instead.
Planning outcomes vary significantly by borough. Conservation area coverage is the single biggest driver — boroughs with heavy CA coverage tend to see more garden room proposals need a full application.
Check boundaries, trees, drainage and any TPOs that might affect siting.
Keep the building under 2.5m near the boundary, single-storey, behind the principal elevation and under 50% of the curtilage.
Obtain an LDC to have legal certainty before investing in construction.
Most garden room suppliers offer a turnkey service with foundations, electrics and insulation.
Garden rooms under 15m² with no sleeping accommodation are usually exempt; those between 15–30m² have conditional exemptions.
London range; varies with specification and site.
Householder application fee (2026). LDC fee is £129.
Statutory target for householder applications.
Usually no, provided the garden room is under 2.5m tall within 2m of a boundary, single-storey, behind the principal elevation, and used incidentally to the house. Larger or taller garden rooms, or those on listed buildings, need a full application.
Incidental uses include overnight stays by the household, but using a garden room as a self-contained residential dwelling or letting it separately would breach permitted development and require a change of use application.
A garden room can be built right up to the boundary but its maximum height is restricted to 2.5m if it is within 2m of any boundary. Beyond 2m it can be up to 4m (dual-pitched roof) or 3m (flat or mono-pitch).
Outbuildings at the side of the house are not PD in conservation areas, and any outbuilding larger than 10m² and more than 20m from the house needs planning permission. Most rear garden rooms within the standard size limits remain PD.
No — this would be a separate dwelling use and would need change of use and likely full planning permission. The incidental-use requirement is strict and is the most common reason enforcement action is taken against garden rooms.
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