Cow Byres and external stone stair at Plas yn Blaenau

Cow Byres and external stone stair at Plas yn Blaenau are two adjoining 2-storey vernacular buildings, oriented north-south, built into a change of ground level. The cow byres are accessed from the east side at yard level, while the living accommodation on the upper floor is entered from the west side at the higher garden level. The buildings are constructed of colourwashed local stone rubble with slobbered mortar, and the south gable is partly built of brick. They feature a gabled slate roof with a clayware ridge.

The south byre has a shallow outshot roof to the west, with slating laid in diminishing courses. To the east, the south byre has a central entrance with a shallow semi-elliptical stone arch, and a bipartite 2/2 pane sash window aligned above it. The north byre has an off-centred entrance with a segmental arch and two symmetrically positioned casement windows above. There is a boarded door leading to the upper floor from the garden on the west side.

A flight of stone stairs rises from the yard to the garden level against the north gable wall. The interior features an open rafter roof with through purlins and trusses with raking struts, similar to those found in farmhouses. There are domestic-type fireplaces and a framed hardwood floor structure over the byre.