Garden room planning permission: the rules that catch people out
The height, position and use limits for garden rooms, sheds and summer houses in England, when building regulations apply, what a certificate costs, and how Wales, Scotland and NI differ.
A garden room in England needs no planning permission if it is single storey, sits behind the front of the house, stays inside the height limits and is used for something incidental to the house rather than lived in. Sheds and summer houses follow the same rules. We set out every limit, the cases where the answer is no, when building regulations apply, what a certificate costs, and how Wales, Scotland and Northern Ireland differ.
Do you need planning permission for a garden room?
For most garden rooms in England, the answer to whether you need planning permission is no. Garden rooms, sheds, summer houses, greenhouses and garden offices are built under permitted development rights, in Class E of the England order, as long as the building meets every limit and is used for a purpose incidental to the house.
The building has to stand apart from the house. A room built against the house is an extension under Class A, with the same 3 metre depth limit, or 4 metres on a detached house, as a conservatory or a kitchen extension.
For a detached building, these are the limits as the Planning Portal's outbuildings guidance sets them out for England.
| Rule | Limit |
|---|---|
| Storeys | Single storey only |
| Eaves height | 2.5 m |
| Overall height, dual-pitched or hipped roof | 4 m |
| Overall height, any other roof | 3 m |
| Any part within 2 m of a boundary | 2.5 m overall |
| Position | Not forward of the wall forming the principal elevation, usually the front of the house |
| Land covered | Outbuildings and extensions together no more than half the land around the original house |
| Verandas, balconies and platforms | None, and any platform no more than 0.3 m high |
| Use | Incidental to the house: not a bedroom, bathroom, kitchen or self-contained home |
| Listed building | Any outbuilding within its grounds needs planning permission |
How big can a garden room be without planning permission?
Planning sets no floor area limit for a garden room in England. The cap is on land: outbuildings and extensions together can cover no more than half the land around the original house, meaning the house as it stood on 1 July 1948, or as built if it is newer. Earlier extensions, sheds and garages all count against that half.
Height is the limit that shapes most designs, because the 2.5 metre cap applies to any part within 2 metres of a boundary, whatever the roof. In a small garden that strip takes more than it seems: on a plot 8 metres wide, a building kept 2 metres from both side fences has 4 metres of width left for anything taller.
Floor area matters for building regulations instead. A detached garden room of up to 15 m², or up to 30 m² set at least 1 metre from every boundary, is exempt from them as long as nobody sleeps in it, so 15 m² and 30 m² are the sizes worth designing to.
Where you can put a garden room
Nothing can go in front of the wall that forms the principal elevation of the house, which is usually the front wall facing the road. Behind that line, any spot that meets the height and land limits is open.
Designated land takes more away. In England that means conservation areas, National Parks, National Landscapes (formerly areas of outstanding natural beauty), the Broads and World Heritage Sites:
- No outbuilding between a side wall of the house and the boundary, in any of these areas.
- In National Parks, National Landscapes, the Broads and World Heritage Sites, buildings more than 20 metres from the house can cover no more than 10 m² in total.
Within the grounds of a listed building, any outbuilding needs planning permission, wherever the house is. Flats and maisonettes have no permitted development rights for outbuildings, and neither do houses created by converting a shop or farm building under permitted development. An Article 4 direction or a condition on the house's original planning permission can remove the rights too, so check in particular on a newer estate.
A veranda or balcony is not permitted development at all, and a deck can be no more than 0.3 metres high, so a garden room with a raised covered porch on a sloping plot can need an application.
Sleeping, toilets and kitchens in a garden room
Class E only covers a building used for a purpose incidental to the house, such as a home office, a playroom, a summer house or storage. The government's technical guidance treats a bedroom, a bathroom or a kitchen as primary living accommodation, which is not incidental, and a self-contained annexe is a separate home.
So the same building can be lawful or not depending on what goes inside. A garden office with a desk is permitted development. The same building with a bed and a shower is not, and needs planning permission.
For a garden office with only a toilet, the test is still whether the building is used for something incidental to the house, and a lawful development certificate is the council's written answer. A bathroom with new plumbing also needs building regulations approval, whatever planning decides.
Do garden rooms need building regulations approval?
Planning and building regulations are separate tests, and a garden room can pass one and fail the other. The exemption for small detached buildings is in Schedule 2 of the Building Regulations 2010, which cover England and Wales.
| Garden room | Approval needed? |
|---|---|
| Up to 15 m², no sleeping accommodation | No |
| Over 15 m² and up to 30 m², no sleeping accommodation, at least 1 m from every boundary | No |
| Over 15 m² and up to 30 m², within 1 m of a boundary, built substantially of non-combustible material | No |
| Over 15 m² and up to 30 m², within 1 m of a boundary, timber-framed | Yes |
| Over 30 m² | Yes |
| Any size, with sleeping accommodation | Yes |
Timber burns, so a timber garden room over 15 m² tucked into a corner within 1 metre of the fence loses the exemption. Moving it 1 metre in, or keeping it to 15 m², keeps it exempt.
The wiring is separate from the building. In England a new circuit run from the house to the garden room is notifiable electrical work under Approved Document P, so use an electrician registered with a competent person scheme, who self-certifies and issues the building regulations compliance certificate within 30 days. In Wales, changes to circuits outdoors have to be notified too.
Lawful development certificates, fees and neighbours
Nobody has to approve a garden room that is permitted development. A lawful development certificate from the council confirms in writing that it is lawful, and it is the proof a buyer's solicitor asks for when you sell. In England a certificate for proposed work costs half the planning fee for the same work, and planning fees rise each April in line with inflation.
Neighbours cannot object to a garden room built within the permitted development limits, because there is no application to object to. If the building needs planning permission, for its size, position or use, neighbours are notified of the application and can object.
Garden room rules in Wales, Scotland and Northern Ireland
The planning limits above are England's. Wales, Scotland and Northern Ireland each set their own permitted development rights for outbuildings, so the limits change at the border.
| Nation | Height | Near a boundary | Land covered | Designated areas |
|---|---|---|---|---|
| England | 4 m dual-pitched, 3 m other roofs; eaves 2.5 m | 2.5 m within 2 m | Half the land around the original house | Nothing beside the house; 10 m² beyond 20 m of the house in National Parks, National Landscapes, the Broads and World Heritage Sites |
| Wales | 4 m with more than one pitch, 3 m single pitch, 2.5 m flat roof; eaves 2.5 m; 1.5 m within 2 m of the house | 2.5 m within 2 m | Half the garden | Nothing beside the house; 10 m² beyond 20 m of the house |
| Scotland | 4 m; eaves 3 m | 2.5 m within 1 m | At least half the front or rear garden left undeveloped | 8 m² footprint in a conservation area; 4 m² within the grounds of a listed building |
| Northern Ireland | 4 m | Eaves 2.5 m within 2 m; not within 3.5 m of a road boundary behind the house | Half the land around the original house | Nothing beside the house in conservation areas, National Parks, AONBs and World Heritage Sites; 10 m² beyond 20 m of the house in the last three |
Wales has run its own planning system since 2016. The Welsh Government's outbuilding rules add two limits England does not have: 2.5 metres for a flat-roofed building anywhere in the garden, and 1.5 metres for any part within 2 metres of the house. Any outbuilding in the grounds of a listed building needs planning permission, and flats and maisonettes have no rights.
Scotland's rules for sheds, garages, sun-houses and greenhouses are Class 3A in planning circular 1/2024. The boundary strip is 1 metre rather than 2, and the eaves can reach 3 metres. A building warrant from the council may be required, so ask its building standards team before ordering.
Northern Ireland's limits are Class D of the Planning (General Permitted Development) Order (Northern Ireland) 2015. It allows no deck, balcony or veranda at all, where England allows a platform up to 0.3 metres, and use as a dwelling is excluded. Building control sits with the district council, under Northern Ireland's own building regulations.
Common questions
How big can my garden room be without planning permission?
A garden room in England has no floor area limit under permitted development, but outbuildings and extensions together can cover no more than half the land around the original house. It must be single storey, 2.5 metres at the eaves, and no more than 4 metres high with a dual-pitched roof or 3 metres otherwise. Within 2 metres of a boundary the limit is 2.5 metres overall.
Can neighbours object to a garden room?
Neighbours cannot object to a garden room that meets the permitted development limits, because no application is made. If the garden room needs planning permission, for its size, position or use, neighbours are notified of the application and can object before the council decides.
Does the 4 year rule apply to outbuildings?
The 4-year rule no longer applies to building work in England, where the council can take enforcement action for 10 years after unauthorised work is substantially complete. The change came in on 25 April 2024, with transitional rules for older work. In Wales the limit for building work is still 4 years.
Can I sleep in my garden room?
A garden room used as a bedroom is not permitted development in England, because a bedroom counts as primary living accommodation rather than a use incidental to the house, so it needs planning permission. Sleeping accommodation also removes the building regulations exemption at any size, so the building needs approval as well.
Do I need planning permission for a garden room with a toilet?
A garden room with a bathroom needs planning permission in England, because a bathroom counts as living accommodation rather than an incidental use. For a garden office with only a toilet, the test is whether the building is still incidental to the house, and a £136 lawful development certificate settles it before the plumbing goes in.
Do I need planning permission for a shed?
A shed needs no planning permission in England if it is single storey, behind the front of the house, 2.5 metres at the eaves and no more than 4 metres high with a dual-pitched roof or 3 metres otherwise, and no more than 2.5 metres within 2 metres of a boundary. Summer houses and greenhouses follow the same rules. Flats, listed buildings and homes with removed rights need an application.
Can I build a 30m2 garden room without planning permission?
A 30 m² garden room can be permitted development in England, because planning sets no floor area limit, only the height, position, use and half-the-land rules. At 30 m² it also stays exempt from building regulations if every part is at least 1 metre from the boundary, or if it is built substantially of non-combustible material.