Do I need planning permission for an extension?
Often not. Here are the permitted development limits in plain English, and when you do need to apply.
Most single-storey extensions we build in Surrey do not need planning permission. They fall under permitted development, a set of rules that let you extend within limits without applying. Here are the limits that matter most.
Single-storey rear extensions
- Up to 4m deep on a detached house, 3m on a semi or terrace, measured from the original rear wall
- Up to 8m and 6m respectively under the larger home extension scheme, but the council must be notified first and neighbours get a say
- No higher than 4m, and no higher than 3m at the eaves if within 2m of a boundary
- Materials similar in appearance to the existing house
Two-storey extensions
- Up to 3m deep and at least 7m from the rear boundary
- Roof pitch matching the existing house
- No windows in side walls unless obscure-glazed and fixed
When you do need to apply
- Flats and maisonettes have no permitted development rights
- Listed buildings and most conservation areas, of which Surrey has many
- Houses where permitted development was removed when the estate was built, which is common on newer developments
- Anything beyond the limits above, or extending forward of the front wall
Building regulations are separate
Even when no planning permission is needed, every extension needs building regulations approval covering structure, insulation, drainage, fire safety and electrics. We handle this through an approved inspector and give you the completion certificate, which you will need when you sell.
If you are unsure, a Lawful Development Certificate from the council confirms in writing that the work is permitted. It costs about half a planning fee and is worth having.