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How high can I build a single-storey extension without planning permission?

A single storey rear extension can fall under permitted development, meaning planning permission may not be required providing it meets certain criteria.  

In terms of height, the extension must:

  • Be no taller than four metres at its highest point
  • Have eaves no higher than the eaves of the original house
  • Not exceed the height of the original dwelling  

Read about planning permission for extensions on Planning Portal

Common Questions

Do summerhouses or garden offices need building regulations approval?

If you plan to put up a small, detached building like a garden shed or summerhouse (classed as an outbuilding) in your garden, 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

What happens if I build without planning permission?

If you carry out development without the necessary planning permission, and it doesn’t fall within permitted development rights, you may be in breach of the planning rules. In such cases, you will usually need to submit a retrospective planning application to seek approval for the work already completed or started. However, there is no guarantee that permission will be granted.  

Learn more about planning breaches on Planning Portal  

Can I pave my front garden to use as a driveway?

You will not need planning permission if a new or replacement driveway of any size uses permeable (or porous) surfacing which allows water to drain through, or if the rainwater is directed to a lawn or border to drain naturally.

If the surface to be covered is more than five square metres planning permission will be needed for laying traditional, impermeable driveways that do not provide for the water to run to a permeable area.

This guidance applies to houses, there are different rules for flats and maisonettes, converted houses, new houses or areas where there permitted development rights may be restricted.

Read about paving your front garden

You may need to consider if a dropped kerb is required, largely dropped kerbs are not a planning matter but you will need to apply to your local council.  

Find out more about dropped kerbs

Do I need planning permission to put up a shed?

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

Do I need planning permission to convert my garage into a workshop?

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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