In most cases it is not needed, as the changes are conducted only on the inside of your building. However, in case of some projects it might become a necessary requirement. For instance, when the plan involves adding an entrance or windows on the front side of the property, digging completely new basement or digging up a pavement or part of the road outside your house, the local council must first provide you with a planning permission.
When you think of extending your rooms or changing its structure in the future, it is advised as well to familiarize yourself with planning permission specifics for basement conversions.
Different regulations apply to a listed building. Before starting any work it is necessary to acquire planning permission, also in the case of changes not visible from the outside.
It is required because such properties are under protection for, for instance historical reasons. Remember, that even if you do not need a planning permission, the conducted work must always comply with building regulations. They are a set of regulations, which apply for all new living space and guarantee the residents’ safety.