What is planning permission?
Planning permission is formal approval from your local council to carry out certain kinds of building work or change how a property is used.
Not every project needs it. Many smaller works are covered by 'permitted development rights', which let you build without a full application if you stay within set limits.
When you usually need permission
Large extensions, changes to the roofline, new dwellings, and work on listed buildings or in conservation areas almost always require permission.
If you are unsure, your council's planning portal is the best first stop, or you can apply for a Lawful Development Certificate to confirm your project is permitted.
How the process works
You submit drawings and a description of the work, pay a fee, and the council consults neighbours and statutory bodies before making a decision, usually within 8 weeks.