If you are looking to fit-out an existing commercial space that was originally granted Planning permission for the same type of use that you are proposing, then you need to apply for a Building Permit through the Building Control section of the Department. This requires selecting an Agent (architect/draftsperson) to submit a permit application through the Online Planning System and the inclusion of pertinent structural, mechanical, electrical and plumbing drawings that apply.
Going through the whole Planning process is required if you are constructing a new building or if you are proposing a change-of-use to an existing commercial space (for example, putting a restaurant into a space previously fit-out as a retail clothing store). Before applying for the building permit (process outlined above), your Agent will need to apply for Planning Permission through the Online Planning System and include the pertinent architectural drawings and land documentation. (View Guidelines)