Hafod Rhug Isaf was probably originally of the early 17th century, with barn and stabling at opposite ends of the house, added later in the 17th or 18th century. The original farmhouse was of one storey with fenestrated attics. The roof is covered with coarse slates and the walls are of mortared rubble on a boulder base. The original openings have rough stone heads and the windows are nearly square.
Source: Caernarvonshire Inventory, Vol II, No. 1294.