Heol-ddu is an eighteenth century gentry farmstead (see NPRN 31610). The main house is dated 1742 (NPRN 17427) and behind this lies the smaller second house. This second house has similar detail to the main house and was built wen the estate was occupied by two brothers.

This is a derelict fully-storeyed symmetrical farmhouse of central-entry type with end chimneys, with a datestone of 1773 in the south-east gable. The house stands at the rear of the principal house, which is dated 1748, and has latterly been used as a dairy and corn-dryer. Much period detail remains, however, including the contemporary two-light windows. See the listing for a full description. Field observation with record photographs in Sept. 2002. (2002.10.09/RCAHMW/RFS)