Platform-sited cottage-farmhouse of crog-lofft type retaining a full cruck-truss. The large footings and platform, which extends beyond the present cottage, suggest that the present house may be a reconstruction of an earlierdwelling. The cottage retains a kitchen/hall open to the roof with a central cruck-truss and a gable-end fireplace. The lower crog-lofft end has lost its ceiling and partition (the gable end has a ledge for the joist ends) but retains a truss with a section of cruck-blade reused as a lapped collar. There is a small lean-to extension on the E. wall. NMRW photographs dating from 1953 show Oerddwr-isaf with a part-rendered stone-tiled roof. The roof slid off in the 1980s earthquake and was replaced with corrugated iron. The house is noted in the Caernarvonshire Inventory II (mon. 709), but the RCAHMW plan (1953) was not included. The house has been uninhabited since the 1960s and is now used as a store. The site is becoming choked with Japanese knot-weed.

Tree-ring dating samples taken in October 2006 as part of the joint Beddgelert Historical Society - RCAHMW dating project. R.F. Suggett/RCAHMW/October 2006.

Additional: Tree-ring dating results reported in Vernacular Architecture 38 (2007):

3. BEDDGELERT, Oerddwr-isaf (SH 5907 4543) Felling date: Winter 1494/5
Purlins 1494(22C), 1474(h/s); Principal rafters (1/2) 1494(21C); Crucks 1494(20C), 1490(15+3C NM); Inserted mantel-beam (0/1). Site Master 1424-1494 BDGLRT21 (t = BDGLRT10; ROYALHS3; ROYALHS1)
An upland farmstead of medieval origin sited about 120m. above O.D. The present house appears to incorporate part of the medieval fabric of a hall-house whose platform extends beyond the present three-bay house. The truncated house was of croglofft type with an upper-end chimney, cruck-truss central to an open hall and passage, and a re-set partition truss with a lapped collar (probably a re-used section of cruck blade) replacing a morticed collar. The fireplace beam was unsuitable for sampling. Description in RCAHMW, Caernarvonshire Inventory II (1960), no. 709, 22. R.F. Suggett/RCAHMW/July 2007.