You can find out if you need planning permission before you start your project, at no cost, by visiting the Planning Portal where you can find a wide range of advice and guidance on the planning system in England. The key features of the Planning Portal are the use of Interactive information and mini-guides for common projects.
Should you prefer written confirmation that your proposal does or does not need planning permission it is possible to apply for a Lawful Development Certification from the Council. This is a formal process in which you would make a planning application by submitting an application form, scaled drawings and the payment of a fee.