This term applies where the contract-holder has not carried out a repair which was their responsibility (see the term Duty to notify landlord of defect or disrepair below).
Mae'r teler hwn yn gymwys os bydd deiliad y contract yn methu ag atgyweirio rhywbeth yr oedd yn gyfrifol amdano (gweler y teler Dyletswydd i hysbysu landlord am nam neu adfeiliad isod).