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What permission do I need to knock through adjoining properties?

Planning permission is not normally required to turn two properties into one by knocking through a party wall provided the changes are internal and do not impact the external appearance of the property.

You should check with your local planning authority that they agree, and there are not any previous planning changes or conditions which may have an impact.

Additional permissions may be required depending on the building’s history and their location. If the building is listed, an application for listed building consent will be required before any major changes are made to the dwellings.

The work will have to comply with building regulations, the focus will be on structural work and safety.

Read more about how building regulations apply to internal walls.

Common Questions

Can I install patio doors to the rear of my house where there is currently a single external door?

Installing patio doors at the rear of your house is likely to fall under permitted development rights, meaning an application for planning permission is not required, provided certain limits and conditions are met.

The doors should be of similar appearance to those previously used, if they are not then generally planning permission will be required.

If you live in a listed building, you will need listed building consent for any significant works.
If you live in a designated area such as a conservation area or national park, then additional restrictions may be in place.

If you are unsure whether the work falls within permitted development rights you can check with your local planning authority or submit a lawful development certificate to prove the change is lawful and prevent any future enforcement action.

Do I need planning permission to demolish a building?

Demolishing a building may require planning permission or prior approval, depending on factors such as the building’s type, size, and location.

Before starting any demolition work, it’s important to consult your local planning authority to confirm what permissions are needed. This helps avoid the risk of enforcement action or legal consequences.

You will also need to ensure you conform to the building regulations around the demolishing of a building.

Read more about demolition.

Do I need planning permission to add a first-floor extension onto an existing ground floor extension?

Adding a storey on top of an extension will always require an application for planning permission.

If you want to add a storey on top of your house under permitted development rights, it must be on the principal part of the house.

If you want to add an additional storey on top of your house, it can be permitted development. It is only permitted development if it follows certain rules:

The current house

  • Is not a building containing one or more flats, or a flat contained within such a building
  • Was constructed between 1 July 1948 and 28 October 2018
  • Has not already had additional storeys added to it
  • Is not on Article 2(3) land or a site of special scientific interest
  • Was not changed to be used as a house (from a previous non-residential use) under permitted development rights.

How many storeys can you add?

  • If the house is one storey then one storey can be added
  • If the house is two or more storeys then two storeys can be added

Where can the storeys be added?

  • The additional storeys must be added to the principal part of the house. The principal part of the house is the main part of the house excluding any front, side or rear extension of a lower height (regardless of these being part of the original house or subsequent additions).
  • Engineering operations must only include works within the existing curtilage of the house to strengthen existing walls and foundations

How high can it be?

  • The house cannot exceed 18 metres in total height
  • Each storey cannot add more than 3.5 metres to the total height
  • If the house is not detached the total height cannot be more than 3.5 metres higher than the next highest building that the house is attached to, adjoins, or is in the same row as.
  • The additional storeys must have an internal floor-to-ceiling height of no more than 3 metres, and no greater than the internal height of any existing storey within the principal part of the house.

What materials can be used?

The materials used must be of a similar appearance to those used in the construction of the exterior of the current house

Where can windows be placed?

Windows must not be placed in any wall or roof slope forming a side elevation of the house.

Following completion of development:

  • The house must remain in use as a domestic residential property
  • No visible support structures must remain on or attached to the exterior of the house
  • The roof pitch of the principal part of the house must be the same as it was prior to the development.

 If any of the limits set out above are exceeded then an application for planning permission will be required. If you are unsure, you should contact your local planning authority.

Find contact details for your local planning authority.

What is a party wall?

A wall is a 'party wall' if it stands astride the boundary of land belonging to two (or more) different owners, for example the wall separating two semi-detached properties.

Some kinds of work carried out to a property may not be controlled by the building regulations, but may be work which is covered by the Party Wall etc. Act 1996. This is a separate piece of legislation with different requirements to the building regulations.

To find out more about party walls, visit Planning Portal.

Can I use an outbuilding as a home office?

Yes, in most cases you can use an outbuilding as a home office without needing planning permission. As long as the use remains incidental to the main dwelling it is still considered part of your domestic residential use.

Read more about outbuildings

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