Do I need planning permission? (UK)
If your proposed extension meets certain conditions, it may be classed as ‘permitted development’ – which means you do not need to apply for planning permission. Generally, the following types of extension may qualify as permitted development:
– Single story extensions to the rear of the house, not exceeding 4m in height, not extending more than 4m (detached house) or 3m (attached house) from the rear of the existing house, where the extension (including previous extensions and outbuildings) does not exceed 50% of the land around the original house.
– Two storey extensions to the rear of the house, extending no more than 3m from the rear of the original house and not within 7m of the opposite boundary, no higher than the existing house, where the extension (including previous extensions and outbuildings) does not exceed 50% of the land around the original house.
– Single storey side extensions no more than 4m in height, with a width no greater than half the width of the original house, where the extension (including previous extensions and outbuildings) does not exceed 50% of the land around the original house.
– Loft conversions within additional volume limits (40m3 for terraced houses; 50m3 for semi-detached and detached houses), not extending beyond the original roof slope at the front of the house (facing the road) and not extending higher than the existing roof.
To be considered permitted development, the materials used for the extension should match the appearance of the existing house (with the exception of conservatories), and there are additional restrictions on the location and type of windows, balconies, eaves height and roof pitch.
We can advise whether your extension meets the conditions for permitted development, but there are some instances when you must apply for planning permission.
Permitted development applies only to houses, not flats, maisonettes or other buildings. Extensions to the front or side facing onto a road are not permitted development.