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Do I Need Planning Permission?

Planning permission is one of the first major hurdles you need to overcome when undertaking any major building or renovation project. New buildings and extensive changes to buildings requires consent from the local planning authority.

However, sometimes it can be difficult to know when you need planning permission. From planning an extension to building a house and everything in between, this post lists the different types of development you may be wishing to carry out and whether you need planning permission to go ahead with your project.

Planning permission is decided by the National Planning Policy Framework and your local planning authority. It is always best to consult your local planning authority as they can help you more clearly decipher whether you need planning permission, and this post acts as guidance only to give you an idea of what to expect.

In some cases, and in many highlighted below, planning permission may not be needed and gaining permitted development rights is sufficient enough to carry out the work. Permitted development allows you to carry out certain projects and more minor and modest works without the need for planning permission. Again, you should consult your local planning authority for further advice.



You need planning permission if:

  • The extension is more than half the area of the land around the original house.
  • It is forward of the principal elevation.
  • It is higher than the highest part of the roof of the existing building.
  • The eaves of the extensions are higher than the eaves of the house.
  • It is a two-storey extension and extends beyond the rear of the house by more than 3m.
  • The materials you use on the extension are not similar to the materials of your property.
  • Your extension includes verandas and balconies.
  • Your two-storey extension is closer than 7m to the rear boundary.
  • If single-storey, your extension is higher than 4m.
  • If a single-storey rear extension, it extends beyond the rear wall of the house more than 3m for an attached house and 4m for a detached house.
  • Your side extension is not single storey and is higher than 4m with a width of more than half of the original building.


If your extension sits within these regulations, you do not need planning permission and work can be carried out under Permitted Development rights.



Conservatories fall under the same regulations as single storey extensions – but as they are normally smaller in size they do not generally require planning permission.



You need planning permission if:

  • The outbuilding is higher than 4m for dual pitch roofs, 3m for other roofs and 2.5m when building within 2m of the boundary.
  • It takes up more than half of the land around the property (the curtilage).
  • Likewise, if you plan to build multiple outbuildings the total area covered by these buildings is more than 50% of the total land around the property.
  • The outbuilding sits forward of the principal elevation.
  • Outbuildings are more than a single storey.
  • The eaves are higher than 2.5m.
  • The use of the outbuilding is not an addition to the main building such as a gym, garage or office, and you plan for it to be residential accommodation – separate to the main building.


If your outbuilding sits within these regulations you can build it under permitted development permission.



If you plan to change the internal space in an existing part of your house such as in a garage, you can do this under permitted development without the need for planning permission, as long as you are not increasing the overall footprint of the building.


Paving Front Garden

You need planning permission if the paving situated between the principal elevation of a house and the highway:

  • Is not made of porous material.
  • Is over 5 square metres.
  • If the paving is not porous and you do not direct surface runoff into a permeable/porous area within the property curtilage.


Windows and Doors

You only need planning permission to change or alter windows if your property is listed.

Bay windows, however, are classed as extensions so the regulations for extensions apply here.

Permission to add a new window or door is not required as long as any upper floor windows on the side elevation are glazed with obscured glass and fixed into a non-opening frame.


Walls and Roof

You do not need planning permission for minor works like painting the walls of your home unless your building is listed.

To add a rooflight, planning permission is required if the rooflight extends forward of the roof plane on the elevation fronting a highway and projects more than 15cm from the roof slope. 

If you want to change the aesthetic of your home, including adding rooflights, you need planning permission if you live in a conservation area or Area of Outstanding Natural Beauty (AONB).


Solar Panels

You will need planning permission for solar panels if:

  • They protrude more than 200mm beyond the plane of the wall or roof.
  • The highest part of the panel is higher than the highest part of the roof.
  • You wish to install solar panels onto a listed building or in a conservation area.


Otherwise, solar panels can be developed under permitted development.


Fences, Gates, Walls

You need planning permission to construct or alter a fence, gate or wall if:

  • The fence, gate or wall is next to a road and over 1m high.
  • It is over 2m and not next to a road.
  • Your property is a listed building.
  • It is part of a boundary with a listed building.



You need planning permission to alter trees if:

  • Your trees are protected by tree preservation.
  • They are in a conservation area.


Internal Remodel

If you do not wish to extend the overall footprint of your property, permitted development allows you to carry out work without full planning permission.


Loft Conversions

You can add dormer windows to your loft with permitted development and without planning permission.

You will need planning permission if your loft is going to be higher than the highest part of your existing roof or extend off the roof plane on the principal elevation.


Home Conversions

If converting two houses into one, such as two flats into one larger home, this can usually be carried out under permitted development.

On the other hand, if you are planning to divide a property into two separate homes, you would need planning permission to go ahead with the conversion.



You need planning permission to build a porch on the front of your property if:

  • Any part of the porch is taller than 3m.
  • It is within 2m of any boundary adjacent to a highway.
  • The ground area is greater than 3m squared.


If your porch plans sit within these regulations you do not need planning permission and can build a porch with permitted development.



Any raised platform higher than 300mm requires planning permission. Garden decking and similar designs below this height do not require planning permission.


Swimming Pools

You can build a swimming pool under permitted development rights in your garden as long as the total area of the pool does not exceed 50% of the total area of your garden.



You do not need planning permission if creating a new vehicle access on an unclassified road. You do require planning permission, however, when creating a new access onto a classified road, as you need to ensure sufficient visibility is maintained when leaving the site and there is sufficient turning space for entering and exiting the area.



You cannot apply cladding to your property if it is located in a special area such as an AONB. If your property does not reside in a special area such as this, you can change cladding under permitted development.



Converting an existing basement into a living space is in most cases unlikely to require planning permission unless:

  • The usage is changed.
  • A light well is added which alters the external appearance of the property.
  • It is a separate unit to your main property.


However, these major works are likely to require planning permission:

  • Excavating the ground beneath your property to create a new basement.
  • Creating a separate unit of accommodation.
  • Altering the external appearance of the house.


Do I Need Planning Permission?

You should you now have a clearer idea of when you need planning permission. From extensions, outbuildings, windows, walls and fences to loft conversions, home conversions, porches, decking, and basements, many of these are dependent on the size of your project, the level of the work to be carried out, highway safety, the area in which your project is being carried out and the impact on the environment, materials used, design, appearance and access.

Remember to consult your local planning authority first for comprehensive advice on whether you require planning permission. Although this can be a lengthy process, if you don’t get planning permission you will be required to reverse any changes you make, so is well worth it!