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 not exceed 3 metres in height or the height of any existing storey in the principal part of the house (measured internally from floor to ceiling)

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.

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 structures for a purpose incidental to the enjoyment of the dwellinghouse.

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

Outbuildings are considered to be permitted development, not needing planning permission, subject certain limits and conditions.

Read about the limits and conditions for outbuildings

Browse our Outbuildings Mini Guide

Adding a personal or commercial glamping pod will often require planning permission due to the size and permanence of the structure.

For personal use, whether you require planning permission depends on the size of the structure. If it’s placed in your garden, then it may be classed as an outbuilding and fall under permitted development rights. This only applies if it is not treated as a new living space which many glamping pods will be. Full details on outbuildings are available on our common project pages.

For commercial use, planning permission will be needed for the addition, where relevant this will also cover the change of use. An application should include any utilities connections or access roads that will be added alongside the pod.

Due to the complex nature of installing a glamping pod, we’d recommend talking to your local planning authority or our Planning Guidance Service.

Adding a porch canopy is classed as permitted development provided it meets the limits and conditions set out in legislation. Where this is the case, no application for planning permission is required.

Porches must meet the following limits:

• the ground floor area (measured externally)would not exceed three square metres.
• no part would be more than three metres aboveground level (height needs to be measured in the same way as for a house extension).
• no part of the porch would be within two metres of any boundary of the dwellinghouse and the highway.

Read our mini guide for additional information on installing a porch.

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Adding air conditioning to your home is considered permitted development provided all the limits and conditions set out in legislation are met. The limits set out the size, placement and quantity of air conditioning units allowed.

If your home is in a protected area such as a Conservation Area then permission will be required. If you live in a listed building then consent will be required.

The installation of air conditioning must comply with building regulations. It is advisable to contact an installer who can provide the necessary advice, preferably one who belongs to either the Microgeneration Certification Scheme or the relevant Competent Person Scheme.

For more information on air conditioning, read our heat pumps common project.

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Building above an attached garage is treated the same as adding a storey to the rest of your home. This is considered to be permitted development, not requiring an application for planning permission provided you meet the set rules and requirements.

You will still need to submit an application for prior approval to your local planning authority.

Read the list of rules and requirements for extending upwards.

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Creating a new basement will usually require planning permission, particularly if it affects the external appearance of the property. For example, installing a lightwell to bring natural light into the basement may be subject to stricter design rules if it is visible from the street, especially at the front of the property, compared to those at the rear or side.

Because basement construction involves significant excavation and structural work, permission is often necessary. It’s recommended that you consult your local planning authority early on to understand what is likely to be considered acceptable before submitting a planning application. Building regulations will also apply to a new or conversion of a basement.

Read further guidance on basements.

Changing from a commercial use (use class E) to residential(use class C3) falls under permitted development rights, meaning an application for planning permission is not required.

To use the permitted development right you must meet the rules and regulations set out in legislation, this includes submitting an application for prior approval to the local planning authority. The full list of conditions is available on the government website, or our online application form will tell you whether you are eligible.

If you are not eligible for the permitted development right, you will have to submit an application for full planning permission.

Find out more about change of use

Deconversion is the process of restoring a previously subdivided house back to its original state as a single property. Merging flats to create a single house may require planning permission, so you should discuss proposals with your local planning authority before starting work.

Read more about converting flats back to a house.

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If the garage will remain in domestic use - for example, as a personal hobby or home workshop - then planning permission is typically not required.  

However, it’s important to check whether there are any planning conditions, covenants, or restrictions attached to your property or the garage itself that may limit or prevent conversion.  

Read about planning permission for garage conversions on Planning Portal.  

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