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. The rules are currently different in England and in Wales.

In England, the volume allowance mostly applies to loft conversions. You can read more on the Planning Portal¹. 

In Wales, volume allowance currently has a more significant role in permitted development, particularly with:

• Conservatories²
• Extensions³
• Loft conversions⁴
• Outbuildings⁵

You can also use our volume calculator to find out the volume of several common development types⁶.

1. https://www.planningportal.co.uk/permission/common-projects/loft-conversion/planning-permission
2. https://www.planningportal.co.uk/permission/common-projects/conservatories/planning-permission
3. https://www.planningportal.co.uk/permission/common-projects/extensions/planning-permission
4. https://www.planningportal.co.uk/permission/common-projects/loft-conversion/planning-permission
5. https://www.planningportal.co.uk/permission/common-projects/outbuildings/planning-permission
6. https://www.planningportal.co.uk/services/professional-portal/volume-calculator