Upper Trefeen

Upper Trefeen is a timber-framed building with an asbestos cement slate roof. The frame features close studding with tension braces on the ground floor between haunched posts, and the front is jettied. The upper floor has herringbone framing, and the gable end is also jettied, likely continuing around the building. The exterior is clad in weatherboarding, similar to the rear outshut.

There is a central added gabled open porch, which has an outer lintel inscribed with "AI EI / II 1718 EM:CAR." This inscription may have been added to an existing porch that features shaped splat balusters on both sides at the upper level. The door is boarded and set within a shaped doorhead. The building has 18th century or early 19th century nine-paned sash windows with moulded architraves. A Phoenix fire insurance mark is attached to the porch, and there is a brick axial stack.

The building was not accessible during the inspection in February 1996.