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Do summerhouses or garden offices need building regulations approval?

If you plan to put up a small, detached building like a garden shed, garden room, garden office, annexe or summerhouse (all classed as outbuildings), building regulations generally won’t apply if the building has a floor area under 15 square metres and does not include any sleeping accommodation.

For buildings with a floor area between 15 and 30 square metres, building regulations approval is usually not needed - as long as the building does not include sleeping accommodation and either:

  • it is at least one metre away from any boundary, or
  • it is built mainly from non-combustible materials.

Read more about the building regulations that apply to outbuildings.

Don't forget to check the permitted development rights for outbuildings.

Common Questions

What rules apply to installing an extractor fan?

Whether you need planning permission to install an extractor fan depends on the size and placement of the fan.

For domestic installations, such as a bathroom or kitchen in your house, planning permission is not generally required. If the change significantly alters the external appearance of your home then permission may be required.

If you live in a listed building, you will need listed building consent for any significant changes.

Larger extractor fans for businesses are likely to require an application for planning permission to be made to the local planning authority. These extractors can impact the local area due to their noise, visibility and odour, as such the planning authority will need to assess the change.

Building regulations relating to ventilation and electrical works will have to be complied with, these are covered by Approved Document F and P respectively.

Read more about building regulations and the requirement for ventilation on our common projects.

What is prior approval?

Certain types of development are granted planning permission by national legislation without the need to submit a planning application. This is known as 'permitted development'. In order to be eligible for these permitted development rights, each 'class' specified in the legislation has associated limitations and conditions that proposals must comply with.

One such condition on certain classes of permitted development is the need to submit an application to the local planning authority for its 'prior approval; or to determine if it’s 'prior approval' will be required.

This allows the local planning authority to consider the proposals, their likely impacts in regard to certain specific factors (e.g. transport and highways) and how these may be mitigated.

For more information on prior approval, read guidance on prior approval consent types.

Is there a maximum height for a new dormer?

Yes, under permitted development, a new dormer must not be higher than the existing highest part of the roof. It should also have materials that are in similar appearance to the existing roof. Additional limits apply in conservation areas and on listed buildings. Read about planning permission for loft conversions on Planning Portal

What are the rules for installing a septic tank in the garden?

Installing a new septic tank in your garden will often require both planning permission, building regulations approval and a septic tank permit.

The planning permission will ensure that the tank is installed in an appropriate location with information being provided to understand any potential implications for the surrounding environment and water.

Building regulations is required for the installation of a septic tank to ensure it meets the drainage and waste disposal standards set out in Approved Document H.

Where possible it is recommended that you connect to an existing public sewer instead of installing a septic tank, this reduces waste entering the waterways.

For more information visit our drains common project or contact your local planning authority.

Is planning permission required for a car port?

A carport can fall under permitted development rights provided it meets certain limits and conditions set out in legislation. If you exceed or fail to meet a requirement then you will require planning permission.

If not attached to the house, a car port will be treated as an ‘outbuilding’. A full list of requirements is available on our outbuildings common project.

Read our outbuilding common project.

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