Extensions

An extension or addition to your house is considered to be permitted development, not requiring an application for planning permission, subject to set limits and conditions. Visit our interactive house and extensions mini guide to find out about the limitations on size and placement of your planned extension. Most extensions of properties require approval under the Building Regulations.

A planning consultant may help with the smooth running of your project and guide you on your planning permission requirements. To find an accurate consultancy quote, explore Studio Charrette's calculators¹.

Explore our interactive guides²

View our extensions mini guide³

The following elements normally have to satisfy the requirements of the Regulations when building an extension:

• Doors and windows⁴
• Drainage⁵
• Electrics⁶
• External walls⁷
• Kitchens and Bathrooms⁸
• Internal walls⁹
• Roof¹⁰

If in doubt you should always consult your local planning authority.

Find your Local Planning Authority ^{(https://www.planningportal.co.uk/find-your-local-planning-authority)}

If your property is a semi-detached or terraced house, you will need to advise adjoining neighbours of your plans under the Party Wall Act 1996.

Find out more about the Party Wall Act 1996¹¹

1. https://www.planningportal.co.uk/permission/home-improvement/planning-consultancy-calculator
2. https://interactive.planningportal.co.uk/detached-house/outside/extensions
3. https://interactive.planningportal.co.uk/mini-guide/extensions-single-storey/0
4. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/building-regulations
5. https://www.planningportal.co.uk/permission/common-projects/drains-and-sewers/building-regulations
6. https://www.planningportal.co.uk/permission/common-projects/electric-vehicle-charging/electric-vehicle-chargers
7. https://www.planningportal.co.uk/permission/common-projects/external-walls/building-regulations
8. https://www.planningportal.co.uk/permission/common-projects/kitchens-and-bathrooms/is-building-regulations-approval-needed-for-work-to-a-kitchen-or-bathroom
9. https://www.planningportal.co.uk/permission/common-projects/internal-walls/what-building-regulations-apply-to-internal-walls
10. https://www.planningportal.co.uk/permission/common-projects/roof/roof-planning-permission
11. https://www.planningportal.co.uk/permission/responsibilities/other-permissions-you-may-require/party-walls