Garden room planning permission UK : Simple guide

Garden Room Planning Permission UK

Do I need Garden Room planning permission?

Modern garden rooms do not usually need a planning application as they fall within permitted development rules under class E. 

This is pre-approved planning permission as long as your Garden room is built subject to some limits and conditions

Basic Garden Room permitted development rules:

• That the garden room is no higher than 2.5m from the ground to the Eaves (if within 2m of boundary)
• That you do not take up more than 50% of your garden area with this or any other buildings
• It is not to be used for living or sleeping accommodation

We have multiple Garden Room plans available that show how to build a Garden Room whilst keeping below the 2.5m height restriction

What are the planning rules for garden rooms?

Outbuildings are considered to be permitted development and do not need garden room planning permission. Subject to the following limits and conditions:

• No outbuilding on land forward of a wall forming the principal elevation.
• Outbuildings and garages are to be single-storey with a maximum eaves height of 2.5 metres. And the 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.
• 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 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 to houses and not to:

• Flats and maisonettes view guidance from the PlanningPortal on flats and maisonettes
• Converted houses or houses created through the permitted development rights to change use as detailed in our change of use section 
• Other buildings
• Areas where there may be a planning condition, Article 4 Direction or other restriction that limits permitted development rights.

Permitted Development for householders – Technical Guidance

Full details are available on the government’s website: Permitted development for householders – Technical guidance

Building Regulations UK

Do I need building regulations approval for a garden room?

The most important factors are:

• Building Regulations do not usually apply unless you want to sleep in it
• Under 15m2 internal floor area can be installed close to any rear boundary
• Over 15m2 and up to 30m2 need to be a minimum of 1m from any boundary*

If you want to put up small detached buildings such as a garden shed, garden room or summerhouse in your garden, Building Regulations (except Part P for Electrical works) will not normally apply if the floor area of the building is less than 15 square metres INTERNAL and contains NO sleeping accommodation.

If the INTERNAL 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. (*As a solution to this it is possible to coat the cedar cladding of your garden room with a non-combustible Intumescent paint for timber and wood, derivatives are available in Water and solvent-based forms with fire ratings of 30, and 60 minutes.)

Complying with Building Regulations.

Part A of the Regulations for structural integrity is fully complied with, ensuring that the building is constructed so that combined dead loads (weight of structural elements), imposed loads (snow, maintenance activities, etc.) and wind loads are accounted for.  Issues addressed cover elements such as the size and bearing of roof timbers relative to the unsupported roof span per guidance issued by NHBC and TRADA.

Part L (does not apply to buildings under 50m2 internal floor area per Regulation 21) takes account of the insulation qualities of walls, roof, floor, doors and windows, and new Building Regulations introduced in April 2014 impose stricter fabric U-Values for England and Wales of: 

Part P In the case of Garden Buildings Part P applies and any work is notifiable to the Local Authority.  Work can be self-certified by an Electrical Installer who is registered as a competent person using aBS7671 electrical installation certificate for every job they undertake, with a copy given to the householder

Frequently asked questions