Orphan buildings are those buildings that have no identified developer, the developer has ceased trading, or the building is over 30 years old.
Adeiladau amddifad yw'r adeiladau hynny nad oes ganddynt ddatblygwr hysbys, mae'r datblygwr wedi rhoi'r gorau i fasnachu, neu mae'r adeilad dros 30 oed.