What do you need planning permission for?

7 minute read

House in process of having extension built

Making changes to your home can be exciting. Moving or remodelling a bathroom, creating an extra room with an extension, or giving the garden a makeover with new decking and a summer house for example – there are lots of possibilities.

Before making any big changes, it’s important to find out whether you need to apply for planning permission. Planning permission is a process you need to go through for certain home improvements and involves asking the local council if you’re able to make the changes. They will check if your plans are suitable and won’t cause any problems, and they will also ask your neighbours for their opinion. If you own a listed building and are looking to extend or alter you will also need to obtain listed building consent. Only once permission has been granted can you begin the identified work.

Once any modifications have been made to your home, you must notify your insurance provider too, as the value of your property may have changed and could impact your annual premium and the amount of cover you have. In some cases, not providing this information could invalidate your policy.


When do you need planning permission?

Below, you can find the changes and renovations you do and don’t need planning permission for. Where planning permission isn’t required, this is known as ‘permitted development’, a term you’ll find used quite a lot below.

The information in this article is correct as of October 2023 for planning permission in England. The regulations may differ if you live in Scotland, Wales or Northern Ireland. Always check with your local council if you’re unsure about whether you do or don’t need planning permission.


Flats and maisonettes are excluded from permitted development rights. To understand what extension options are available for these types of property, please consult either your local council or a qualified architect. 


Do you need planning permission for an extension?

Whether you need planning permission for an extension mainly depends on the size of the extension, where it will sit in relation to boundaries and the materials that will be used.

Only extensions that meet the below design specifications will be considered permitted development and therefore might not need planning permission.


  • Your extension takes up no more than 50% of land around the "original house"  (the original house is how the property was in 1948 or after this date, how it was newly built)
  • Your extension is not forward of the principal elevation (front of the house)
  • Your extension is not higher than the highest part of the roof 
  • In the case of single-storey extensions, if your home is detached it can not extend beyond the rear wall of the original house by more than 8 metres. For other types of homes, this is reduced to no more than 6 metres 
  • Your single-storey rear extension cannot be higher than 4 metres
  • Extensions of more than one storey must not extend beyond the rear wall of the original house by more than 3 metres
  • Side extensions must be single-storey with maximum height of 4 metres and a width no more than half that of the original house
  • Two-storey extensions must be no closer than 7 metres to rear boundary
  • The materials have to be similar in appearance to the existing house
  • Your extension cannot include verandas, raised platforms, balconies (except Juliet style)
  • Any upper-floor, side-facing windows must use obscure-glazed and ensure any opening is 1.7m above the floor

These regulations may differ if your house is built on designated land – this is land that sits on or within a conservation area, a place of outstanding natural beauty, a World Heritage site or a National Park – so do check the exact rules with your local council before assuming that you do or don’t need planning permission.


Do you need planning permission for a conservatory?

A conservatory will need to meet the same design criteria as listed for an extension above. You will also need planning permission for a conservatory if:

  • You live on designated land and the conservatory will be built on the side of the property
  • You live on designated land and the conservatory will be cladded with stone, pebble dash, timber, plastic, tiles, artificial stone or render
  • You plan on building a side conservatory that will be taller than four metres, or taller than three metres when closer than two metres to a boundary.

As long as your conservatory meets the rules set out under the extension section and none of the above points apply, then it is likely your conservatory will fall within permitted development and you won’t need full planning permission.


Do you need planning permission for a loft extension?

It is unlikely that you will need planning permission for a loft extension in England if:

  • You only want to add 50 cubic metres or less of additional roof space for detached and semi-detached houses (40 cubic metres for terraced houses)
  • Your loft extension will use similar building materials to the existing house
  • The development must not include a window in any wall or roof slope forming a side elevation 
  • The roof pitch of the principal part of the dwelling must be the same as the roof pitch of the existing house
  • Any dormer wall must be set back at least 20cm from the existing wall face
  • Your extension windows must be non-opening if less than 1.7m from the floor level
  • All side windows must be obscured/frosted

The rules around loft conversions and extensions can be confusing, so do visit the Planning Portal website for all the information. The Planning Portal was established by the UK Government in 2002 and is the home of planning and building regulations information and the national planning application service for England and Wales.

It’s worth noting that a loft conversion is different to that of a loft extension, and so if you’re not altering the size of the loft, you may not need planning permission. You might, however, require a building inspection upon the completion of work to ensure it adheres to Building Regulations and is signed off.


Do you need planning permission for a porch?

The planning permission rules for porches are a little simpler than extensions and conservatories.

You can build a porch without planning permission, as long as it meet the below specifications: 

  • The ground floor area (measured externally) does not exceed 3 square metres
  • No part of the porch is more than 3 metres above ground level 
  • No part of the porch is within 2 metres of any boundary of your home and the main road


Do you need planning permission for a shed?

A shed is considered an outbuilding, which, according to Planning Portal, also includes garages, greenhouses, playhouses, saunas, summer houses, kennels and even swimming pools. This means, for all of these structures, the planning regulations are the same.

An outbuilding, such as a shed, won't need planning permission if:

  • It has a maximum eaves height of 2.5 metres and a total height of no more than 4 metres (if it has a dual-pitched roof) or 3 metres for any other type of roof
  • It will be less than 2.5 metres in height and further than two metres from a boundary
  • It does not have a veranda, balcony or raised platform
  • It won't take up more than half the land of the original house, other outbuildings (such as sheds) should be added to the total too

Many standard sheds meet these specifications, so your shed should generally be considered permitted development. However, before installing, you should check that the height will fall within the above limits.

Remember: Listed buildings and homes in designated land have different rules, so check with your local council before any changes are made to these types of homes. 


Do you need planning permission for a summer house?

A summer house counts as an outbuilding, which means the same rules apply as they do for a shed above.


Do you need planning permission for a pergola?

Pergolas also count as outbuildings, and so the same rules also apply as above for sheds.


Do you need planning permission to convert a garage?

Planning permission is not usually required, providing the work is internal and does not involve enlarging the building.

If your intention is to convert a garage into a separate house (regardless of who will occupy it), then planning permission may be required no matter what work is involved. We advise that you discuss such proposals with your local planning department to ensure that any work you do is lawful and has the correct permissions.


Do you need planning permission for decking?

You may need planning permission for decking and other raised platforms if the total height will be more than 30cm above the ground and if their total area covers more than 50% of the garden area, together with extensions and outbuildings.


Do you need planning permission for solar panels?

Solar panels are usually considered permitted development and so it’s very rare that you will need to apply for planning permission prior to installation. If you’re unsure or believe your circumstances differ to those of a regular property, you should contact your local council and discuss your situation and requirements.


Seek confirmation from your local council 

Some of the planning elements are very specific, especially when it comes to large changes to your home, such as extensions, conservatories and outbuildings. If in doubt, you should always confirm with your local council the changes you want to make, and they will advise whether they fall under permitted development or not.


For more home advice, why not try exploring the rest of Age Co's Useful Articles? You can also learn more about Age Co Home Insurance here.