"Rules governing outbuildings apply to sheds, playhouses, greenhouses and garages as well as other ancillary garden buildings such as swimming pools, ponds, sauna cabins, kennels, enclosures (including tennis courts) and many other kinds of structure for a purpose incidental to the enjoyment of the dwellinghouse."

​

Essentially, if you plan to use your garden room as living accommodation or it does not comply with the Permitted Development allowances, you will need planning permission.

If you are unsure if your planned building falls into the category of 'outbuildings' or if you are unsure if planning permission is required, you're best advised to contact your local planning authority.

A garden room with an internal floor area of up to and including 30 metres square is exempt from the current building regulations. There are a couple of caveats to do with how far from the boundary the building is though:

• Garden Rooms with an internal floor area up to and including 15 sq.m - Building regulations do not apply.

• Garden Rooms with an internal floor area between 15 sq.m and 30 sq.m - Building regulations do not apply as long as the building is 1 metre from any boundary.

​

If you do need to comply with the regulations, don't worry! We're well versed and have been working closely with one of the top rated independent Building Control Services in the country (we also build houses!) for over a decade.

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

• 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.

• 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.

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

• No more than half the area of land around the "original house"* would be covered by additions or other buildings.

• 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.

• Within the curtilage of listed buildings any outbuilding will require planning permission.

​

*The term "original house" means the house as it was first built or as it stood on 1 July 1948 (if it was built before that date). Although you may not have built an extension to the house, a previous owner may have done so.

*Designated land includes national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

Please note: The permitted development allowances described here apply only to houses and not to:

• Flats and maisonettes (view the guidance on flats and maisonettes) 

• Converted houses or houses created through the ‘permitted development’ rights for:

  • ‘Changes of use’ (Schedule 2, Part 3, Classes G; M; MA; N; P; PA and Q) (as detailed in the change of use section)

  • ‘New Dwellinghouses’ (Schedule 2, Part 20)

• Other buildings

• Areas where there may be a planning condition, Article 4 Direction or other restriction that limits permitted development rights.

You are strongly advised to read the technical guidance document produced by the Government to help understand how permitted development rules might apply to your circumstances. You can view a copy of 'Permitted development for householders – Technical guidance' on Gov.uk here.