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What are permitted development volume limits?

To qualify as permitted development some household building work projects – notably extending a house – must not exceed limits to the volume being added.  

In England, the volume allowance mostly applies to loft conversions. You can read more on the Planning Portal. 

Use the volume calculator to find out the volume of several loft conversion and extension types.

Common Questions

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.  

Do I need building regulations approval for alterations to or installation of electrics?

If you're doing electrical installation work in your home or garden in England or Wales, you must follow the building regulations. It's recommended to hire an installer who is registered with a competent person scheme (a registered competent person’) who can self-certify that the work meets the required standards.

What is permitted development?

Permitted development rights allow certain types of work to be carried out without the need to apply for planning permission. It typically covers things like small extensions, loft conversions and outbuildings, provided they meet specific size and location limits. These rights can vary or be removed in areas like conservation zones and by Article 4’s, so it’s best to check before proceeding.  

Read about permitted development and Article 4 directions on Planning Portal

Is there a maximum height for a new dormer?

Yes, under permitted development, a new dormer must not be higher than the existing highest part of the roof. It should also have materials that are in similar appearance to the existing roof. Additional limits apply in conservation areas and on listed buildings. Read about planning permission for loft conversions on Planning Portal

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

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