If you live in a house (not a flat or a maisonette) or run a business, you may be able to make alterations to your property without needing to make a planning application, depending on some limits and conditions. These rights are called 'permitted development rights'.
If you think that your development would fall within permitted development rights, we recommend that before carrying out works, you apply to the council for a 'certificate of lawfulness'. This is an optional application that asks the council to confirm in a legal document that the proposed works would be lawful (that they would comply with the legislation). A certificate can give peace of mind before you start works, and may be required during any future sale of your property. It is strongly recommended that you apply for a certificate of lawfulness before starting works, because the legislation can be difficult to interpret, and it is not uncommon for people to make mistakes in interpretation.
If you are thinking of making alterations to your property, read the online guidance on the Planning Portal and on the following pages of this guide.