Lower Trethinna Cottage

Lower Trethinna Cottage is a small house, likely built in the late 17th century. It features rendered and painted stone rubble walls and a corrugated asbestos roof with gable ends. On the left side, there is a large projecting stone rubble end stack. The layout consists of a two-room and cross passage plan, with a larger hall kitchen on the left, heated by the end stack, and a small unheated room on the right. There is also a small 20th-century service extension on the right.

The exterior is two storeys high with an asymmetrical two-window front. The entrance is located to the left of centre and includes a small 20th-century porch. To the left of the porch is a 20th-century window, while to the right is a small window that dates from the 19th or 20th century. On the first floor, there are two casement windows from the 19th or 20th century.

Inside, the large, wany floor joists above the hall kitchen are chamfered, with some featuring stop-chamfers with run-out stops. The chamfered timber lintel above the fireplace suggests that the fireplace has been slightly narrowed. The floor joists above the right-hand room were replaced in the 20th century.