Belfast·SPG004 Residential Extensions and Alterations·Page 9·2.3.1(a)
Certificates of Lawfulness - Existing Use or Development
You can apply for a Certificate of Lawfulness of Existing Use or Development to confirm that an existing use of a building is lawful for planning purposes.
'Certificate of lawfulness of existing use or development' where you want to be certain that the existing use of a building (or any part thereof) is lawful for planning purposes
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/belfast/SPG004 Residential Extensions and Alterations.pdf