Oerddwr Isaf is an upland farmstead of medieval origin situated in the parish of Beddgelert. The present house is thought to incorporate part of the medieval fabric of a hall-house whose large footings or platform extends beyond the present three-bay house. The present house has a croglofft with an upper-end chimney, a central cruck-truss above an open hall and a passage. Its timbers have a felling date of the winter of 1494/5.

This photograph was taken in 1953 during a survey by the Royal Commission and the figure in the doorway is Peter Smith, building investigator. It shows Oerddwr-isaf with a part-rendered stone-tiled roof. The roof slid off in the 1980s earthquake and was replaced with corrugated iron. It has been uninhabited since the 1960s and is now used as a store.

http://www.coflein.gov.uk/en/site/16620/images/OERDDWR-ISAF/