Belfast·SPG004 Residential Extensions and Alterations·Page 8·2.2.4
Checking if planning permission is required
Householders should consult the Planning Portal or contact the council if unsure whether their extension or alteration needs planning permission.
Advice on when planning permission is required can be found on the Planning Portal. However, if you are in any doubt as to whether or not you require planning permission, please contact the council for advice.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/belfast/SPG004 Residential Extensions and Alterations.pdf