That will depend upon many factors including:
If the property is in a Conservation area, has had permitted development rights removed, or the property is listed, further statutory approvals may be required prior to any works starting.
KMASS can assist in advising you what is required and they have the required skills and expertise to guide you through these processes and in more complex cases we can advise details of, and involve, Planning Consultants and other experts with whom we regularly engage and who may be required to assist as necessary.