16th century or earlier, cruck, unusual open timber roof original screen, 1 storey, L shaped, rough hewn slate, original stone staircases.
Wallpaintings; Series of painted shields on headbeam of dais partition.

Additional:
Hafod Yspyty is a classic upland hallhouse of north-western (Gwynedd) type, i.e. cruck-framed and stone-walled. There are two main phases:
(1) c. 1500. A three-unit hallhouse of 'gentry' type with a two-bay hall with central, open truss with cusped apex and double-pegged archbrace. The two-door dais-end partition survives. The partition is of post-and-panel type survives and the inner-rooms appear to have had a ceiling of post-and-panel type.
(2). c. 1600 Inserted hall ceiling and chimney with fireplace stair creating a house of lobby-entry type.
See the plan and description by Peter Smith in The History of Merioneth, Vol. II: The Middle Ages (2001), ed. J & Ll. Beverley Smith, pp. 450 & 482.
R.F. Suggett/RCAHMW/October 2011