20 and 21 St John's Terrace and garden wall to south

20 and 21 St John's Terrace are two adjoining houses built in the mid-19th century, along with a front garden wall. The houses feature walls made of Killas rubble, some of which are roughly coursed, with granite quoins, jambstones, and lintels. They have hipped roofs covered with asbestos slate. Number 20 has wide eaves and a double-depth plan with one room width, while Number 21 has a two-room plan with a parallel range at the rear that extends beyond the side wall of the front part.

Both houses are two storeys tall and face south. Number 20, on the left, has a two-window front with an entrance located under the second window. It features 20th-century windows, a door, and a porch. Number 21 has a symmetrical two-window front with a central doorway, a latticed porch, and original hornless 12-pane sash windows, along with shallow brick arches and lead flashing beneath the slate sills.

The interior has not been inspected. The front is bordered by a low granite coped rubble wall, topped with 20th-century pierced concrete panels for Number 20. These houses are part of a row of similar contemporary homes in St John's Terrace, creating an impressive group despite some later alterations to individual houses.