Building approval is needed before construction can start on most types of building work.
You can get building approval from your local council / authority or a building certifier. All building certifiers must be licensed. You can find licensed building certifiers here.
Building certifiers manage the building approval and inspection process with all relevant practitioners. This helps ensure that all aspects of the building work is compliant. They can also advise whether a building approval is needed, as some minor building work may not require an approval (i.e. accepted development). Depending on the nature of the building work, there may be development functions that must be arranged through your local council or authority.
Please contact your local council or authority for more information.