Plas Uchaf

The early history of the building is not documented. The original construction was thought to date from the late 14th or early 15th century, but part of the structure has been dated to 1435 by tree-ring dating. This is thought to be consistent with its use as the seat of the barons of Cymmer-yn-Edeirnion. In the 16th century the hall was divided horizontally by the addition of an inserted floor supported by moulded cross beams.

The house consists of a long rectangle divided by a cross passage. The west end is a large hall some 25 ft high. The east end consists of smaller rooms on two floors. The roof structure is substantial, of paired cruck beams with additional horizontal, vertical and diagonal bracing. One unusual feature is that the truss between the cross-passage and hall is an aisle truss, a form normally only found in much larger buildings such as barns and churches. This suggests the use of English craftsmen and is an indication of the status of the original inhabitants. The walls are of stone rubble but were originally half-timbered.