Plas-y-Wern mansion is set in a wooded hollow by the Afon Llethi. It is a late medieval house reconfigured in the early 16th century and much altered in the 1670s when what is almost a complete mansion was added on the west end. The house appears to have been tenanted from a comparatively early date. It was restored in the 1930s when an extension was added on the rear north side.
The medieval house is the south-east part of the present building. It is thought to have been a first floor hall, open to the fine surviving roof. Its western end wall has been removed by the seventeenth century work. This house was reconfigured as a three storey block in the early sixteenth century, with the addition of a large projecting chimney breast on the east, a projecting bay on the south and a small staircase and parlour block on the north.

The 1670s work is a grand double pile block with belled swept roofs, hipped to the west. It is a two storey building above a basement and with attics above. It faces south, presenting a three bay whitened facade with five large sash windows and a grand doorway in the eastmost bay next to the earlier work. The impression given is that only half of an intended symmetrical house was achieved.

The house retains some outstanding seventeenth century interiors. The main door opens in to a passage to the main full height stair at the rear. On the north side are the dining room and drawing room with the master bedroom and the eighteenth century library above. The ground floor of the medieval house was more recently the kitchen. The 1930s extension might have included a chapel.

The OS 1st edition County series (Cardigan. XXIV.6 1890) shows the grounds in some detail. Although the mansion had long been a farmhouse by this time there are some indications of an earlier garden layout. The remains of a paved court have been noted on the north side of the house and the main approach, by an avenue from the old road north of the river, led into it.

There is a collection of farmbuildings on the rising ground south of the mansion. These include a late medieval-17th century cruck built house later converted as a barn (NPRN 31557), a two storey cartshed range (NPRN 31558), the remains of a long cowhouse range (NPRN 31559) and a small barn (NPRN 31561) fitted with a waterwheel (NPRN 24797).

Sources: Transactions of the Cardigan Antiquarian Society 2.1 (1915), 53-5
Western Mail for 03.12.1929
NMR Site File

John Wiles 27.09.07