Do I need planning permission for a garden room or log cabin?

Short answer: most garden rooms and log cabins in England don't need planning permission, as long as they stay within a set of size and position limits called permitted development – rights that let you build certain things without applying. Go outside those limits, or live in certain protected places, and you will need to apply.

The official limits

These are quoted from the Planning Portal's outbuildings guidance (the government's planning website). The plain-English notes are ours.

1. Not in front of the house

“No outbuilding on land forward of a wall forming the principal elevation.”

The principal elevation is usually the front of the house facing the road. A cabin in the back garden is fine; one in the front garden needs permission.

2. Height

“Outbuildings and garages to be single storey with maximum eaves height of 2.5 metres and maximum overall height of four metres with a dual pitched roof or three metres for any other roof.”

The eaves are where the roof meets the top of the wall. A dual pitched roof slopes down on two sides, like a house (log cabin sellers call this an apex roof). A pent roof slopes one way and falls under “any other roof”.

3. Lower near a boundary

“Maximum height of 2.5 metres in the case of a building, enclosure or container within two metres of a boundary of the curtilage of the dwellinghouse.”

The curtilage is your house and garden. This is the rule that catches most people out: if your cabin will be within two metres of a fence or hedge line, the whole building must be no taller than 2.5 metres. That's why many sellers advertise cabins “under 2.5m”. Remember the base adds height too.

4. No verandas or raised decks

“No verandas, balconies or raised platforms (a platform must not exceed 0.3 metres in height)”

A covered veranda built into the cabin, or decking more than 30cm off the ground, takes you outside permitted development.

5. No more than half the garden

“No more than half the area of land around the ‘original house’ would be covered by additions or other buildings.”

The “original house” means the house as first built (or as it stood on 1 July 1948 if older). Extensions and other sheds count towards the half.

6. Protected areas

“In National Parks, the Broads, Areas of Outstanding Natural Beauty and World Heritage Sites the maximum area to be covered by buildings, enclosures, containers and pools more than 20 metres from the house to be limited to 10 square metres.”

“On designated land buildings, enclosures, containers and pools at the side of properties will require planning permission.”

Designated land, the Planning Portal explains, includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites. If you're in a conservation area, check with your council early.

7. Listed buildings

“Within the curtilage of listed buildings, any outbuilding will require planning permission.”

8. Not a separate home

Permitted development covers buildings used for a purpose “incidental to the enjoyment of the dwellinghouse” – a home office, gym, hobby room or summerhouse. The Planning Portal says it does not cover “use as separate self-contained living accommodation”. A garden annexe someone lives in is a different matter and needs advice from your council.

These rights also apply to houses only: if you live in a flat or maisonette, see the Planning Portal's guidance for flats and maisonettes.

Building regulations: a separate question

Planning permission is about whether you can build it at all. Building regulations are minimum standards for how it's built (safety, fire, structure). The Planning Portal says:

“If you want to put up small detached buildings such as a garden shed or summerhouse in your garden, building regulations will not normally apply if the floor area of the building is less than 15 square metres and contains NO sleeping accommodation.”

“If the floor area of the building is between 15 square metres and 30 square metres, you will not normally be required to apply for building regulations approval providing that the building contains NO sleeping accommodation and is either at least one metre from any boundary or it is constructed substantially of non-combustible materials.”

In practice: a timber cabin under 15 m² with no bed is normally fine. Between 15 and 30 m², keep a timber cabin at least one metre from your boundaries. Our comparison pages show each cabin's floor area to help – but note sellers' sizes are usually external, and the rules talk about floor area, so check the internal size too.

Electrical work in a garden room is a separate matter again: use a registered electrician who can certify the work.

When in doubt

• Ask your council's planning team, or apply for a lawful development certificate – official confirmation that your plan doesn't need permission.
• Read the government's permitted development technical guidance for the detailed version, with diagrams.

Next: compare cabins that fit – start with cabins for small gardens or browse all cabins by floor area.