Additional storeys/Extending upwards

Building regulations approval is required to add additional storeys to an existing building to make it into a liveable space.

This section provides guidance for adding an additional storey to an existing house which is no more than two storeys high. Requirements for additional storeys to houses over three storeys or flats will be similar but may be more extensive and possibly extend to other parts of the building.

The regulations will be applied to ensure, for example:

• the structural strength of the new floor is sufficient
• the stability of the structure (including the existing roof) is not endangered
• safe escape from fire
• safely designed stairs to the new floor
• reasonable sound insulation between the conversion and the rooms below.

Further information

The following common work sections give an indication of several other elements normally required to satisfy the requirements of the Regulations when building an additional storey on to a house:

• Doors and windows¹
• Drainage²
• Electrics³
• External walls⁴
• Internal walls⁵
• Kitchens and Bathrooms⁶
• Roofs⁷

1. https://www.planningportal.co.uk/permission/common-projects/doors-and-windows/building-regulations
2. https://www.planningportal.co.uk/permission/common-projects/drains-and-sewers/building-regulations
3. https://www.planningportal.co.uk/permission/common-projects/electrics/building-regulations-general-information
4. https://www.planningportal.co.uk/permission/common-projects/external-walls
5. https://www.planningportal.co.uk/permission/common-projects/internal-walls/what-building-regulations-apply-to-internal-walls
6. https://www.planningportal.co.uk/permission/common-projects/kitchens-and-bathrooms/building-regulations-need-for-additional-ventilation
7. https://www.planningportal.co.uk/permission/common-projects/roof/building-regulations-work-to-an-existing-roof