Bydd y gwaharddiad hefyd yn gymwys i adeiladau presennol pan fo gwaith adeiladu perthnasol yn mynd rhagddo sy'n dod o fewn cwmpas y Rheoliadau Adeiladu, oni bai bod y gwaith adeiladu wedi dechrau ar y safle neu fod hysbysiad cychwynnol, hysbysiad adeiladu neu gynlluniau llawn wedi'u cyflwyno a bod y gwaith yn dechrau ar y safle o fewn cyfnod o 8 wythnos.
The ban will also apply to existing buildings where relevant building work is being carried out which falls within the scope of the Building Regulations, unless the building works have started on-site or an initial notice, building notice or full plans have been deposited and work has started on site within a period of 8 weeks.